Vendor dependenciesvendor

Just testing how CI works with this. I tend to prefer vendoring, as it
means that if you have a copy of the code *you can always build it*.
Even if you're 20 years in the future

This is the output of

```
cargo vendor --versioned-dirs
```

12 files changed, 2459 insertions, 0 deletions

diff --git a/vendor/cassowary-0.3.0/.cargo-checksum.json b/vendor/cassowary-0.3.0/.cargo-checksum.json
new file mode 100644
index 00000000..9fb95682
--- /dev/null
+++ b/vendor/cassowary-0.3.0/.cargo-checksum.json
@@ -0,0 +1 @@
+{"files":{"CHANGELOG.md":"3a9b7f3f8bb314b2f5f7fcd3504e249f69f95765a9800d613b8e9762a4d8855e","Cargo.toml":"9ab348a432e2a3b62ff6c8213db8000e61206d04b9e12ac7e29355bb92093079","LICENSE-APACHE":"38b4da6afcf8d01bf9fae5b09dc5446a4e166556b7d66f3ba03305f6c05188ed","LICENSE-MIT":"190ca8d01e23551e4f49e9601a2ca1a740a4a3a9270ad3b5c70f044b8972ef50","README.md":"1654f0b6cd68714752dc60e4386431808e790a69f70f1c3d5524d44a2bd6ae57","src/lib.rs":"1b5b92de9a5f6d7dfc807bf0a618b6175ea8bc894c58d4b77d46cff7849ed6e2","src/operators.rs":"820b4fcffab885883ba9900a12da31e858014280fc226756635eafb7f671cdda","src/solver_impl.rs":"ebde682191f4f5f9aba0b193a25ace54fd25d07facec10fca58a9883dcf794b2","tests/common/mod.rs":"29648db4ecd903a19fffceff5da00bf6707750adc2ceefa350d3adbd95a3eca2","tests/quadrilateral.rs":"411502da8e70f49d474c81e8d43520500880552e45eaefe652145578e7f7add9","tests/removal.rs":"8e0f45ad6ea55315f105973fc78aa4e1546d0a0816d7be12999afd8b75b7efd0"},"package":"df8670b8c7b9dae1793364eafadf7239c40d669904660c5960d74cfd80b46a53"}
\ No newline at end of file
diff --git a/vendor/cassowary-0.3.0/CHANGELOG.md b/vendor/cassowary-0.3.0/CHANGELOG.md
new file mode 100644
index 00000000..f1385db0
--- /dev/null
+++ b/vendor/cassowary-0.3.0/CHANGELOG.md
@@ -0,0 +1,18 @@
+# 0.3

+

+* Various fixes (PR #4) from @christolliday. 

+  Main breaking change is that variables no longer silently initialise to zero and will report

+  their initial value in the first call to `fetch_changes`, also `has_edit_variable` now takes `&self`

+  instead of `&mut self`.

+

+## 0.2.1

+

+* Fixed crash under certain use cases. See PR #1 (Thanks @christolliday!).

+

+# 0.2.0

+

+* Changed API to only report changes to the values of variables. This allows for more efficient use of the library in typical applications.

+

+# 0.1

+

+Initial release

diff --git a/vendor/cassowary-0.3.0/Cargo.toml b/vendor/cassowary-0.3.0/Cargo.toml
new file mode 100644
index 00000000..31b2abb8
--- /dev/null
+++ b/vendor/cassowary-0.3.0/Cargo.toml
@@ -0,0 +1,25 @@
+# THIS FILE IS AUTOMATICALLY GENERATED BY CARGO
+#
+# When uploading crates to the registry Cargo will automatically
+# "normalize" Cargo.toml files for maximal compatibility
+# with all versions of Cargo and also rewrite `path` dependencies
+# to registry (e.g. crates.io) dependencies
+#
+# If you believe there's an error in this file please file an
+# issue against the rust-lang/cargo repository. If you're
+# editing this file be aware that the upstream Cargo.toml
+# will likely look very different (and much more reasonable)
+
+[package]
+name = "cassowary"
+version = "0.3.0"
+authors = ["Dylan Ede <dylanede@googlemail.com>"]
+description = "A Rust implementation of the Cassowary linear constraint solving algorithm.\n\nThe Cassowary algorithm is designed for naturally laying out user interfaces using linear constraints,\nlike 'this button must line up with this text box'.\n"
+homepage = "https://github.com/dylanede/cassowary-rs"
+documentation = "https://dylanede.github.io/cassowary-rs"
+readme = "README.md"
+keywords = ["constraint", "simplex", "user", "interface", "layout"]
+license = "MIT / Apache-2.0"
+repository = "https://github.com/dylanede/cassowary-rs"
+
+[dependencies]
diff --git a/vendor/cassowary-0.3.0/LICENSE-APACHE b/vendor/cassowary-0.3.0/LICENSE-APACHE
new file mode 100644
index 00000000..462333df
--- /dev/null
+++ b/vendor/cassowary-0.3.0/LICENSE-APACHE
@@ -0,0 +1,201 @@
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diff --git a/vendor/cassowary-0.3.0/LICENSE-MIT b/vendor/cassowary-0.3.0/LICENSE-MIT
new file mode 100644
index 00000000..e8d11a44
--- /dev/null
+++ b/vendor/cassowary-0.3.0/LICENSE-MIT
@@ -0,0 +1,21 @@
+The MIT License (MIT)

+

+Copyright (c) 2016 Dylan Ede

+

+Permission is hereby granted, free of charge, to any person obtaining a copy

+of this software and associated documentation files (the "Software"), to deal

+in the Software without restriction, including without limitation the rights

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+copies of the Software, and to permit persons to whom the Software is

+furnished to do so, subject to the following conditions:

+

+The above copyright notice and this permission notice shall be included in all

+copies or substantial portions of the Software.

+

+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE

+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,

+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE

+SOFTWARE.

diff --git a/vendor/cassowary-0.3.0/README.md b/vendor/cassowary-0.3.0/README.md
new file mode 100644
index 00000000..ba38947a
--- /dev/null
+++ b/vendor/cassowary-0.3.0/README.md
@@ -0,0 +1,54 @@
+# cassowary-rs

+

+[![Build Status](https://travis-ci.org/dylanede/cassowary-rs.svg?branch=master)](https://travis-ci.org/dylanede/cassowary-rs)

+

+This is a Rust implementation of the Cassowary constraint solving algorithm

+([Badros et. al 2001](https://constraints.cs.washington.edu/solvers/cassowary-tochi.pdf)).

+It is based heavily on the implementation for C++ at

+[nucleic/kiwi](https://github.com/nucleic/kiwi). The implementation does

+however differ in some details.

+

+Cassowary is designed for solving constraints to lay out user interfaces.

+Constraints typically take the form "this button must line up with this

+text box", or "this box should try to be 3 times the size of this other box".

+Its most popular incarnation by far is in Apple's Autolayout

+system for Mac OS X and iOS user interfaces. UI libraries using the Cassowary

+algorithm manage to achieve a much more natural approach to specifying UI

+layouts than traditional approaches like those found in HTML.

+

+This library is a low level interface to the solving algorithm, though it

+tries to be as convenient as possible. As a result it does not have any

+intrinsic knowledge of common user interface conventions like rectangular

+regions or even two dimensions. These abstractions belong in a higher level

+crate.

+

+For more information, please read

+**[the documentation](https://dylanede.github.io/cassowary-rs)**.

+

+## Getting Started

+

+Add the following to your Cargo.toml:

+

+```toml

+[dependencies]

+cassowary = "^0.3.0"

+```

+

+Please read the documentation (linked above) for how to best use this crate.

+

+## License

+

+Licensed under either of

+

+ * Apache License, Version 2.0, ([LICENSE-APACHE](LICENSE-APACHE) or

+   http://www.apache.org/licenses/LICENSE-2.0)

+ * MIT license ([LICENSE-MIT](LICENSE-MIT) or

+   http://opensource.org/licenses/MIT)

+

+at your option.

+

+### Contribution

+

+Unless you explicitly state otherwise, any contribution intentionally submitted

+for inclusion in the work by you, as defined in the Apache-2.0 license, shall be

+dual licensed as above, without any additional terms or conditions.

diff --git a/vendor/cassowary-0.3.0/src/lib.rs b/vendor/cassowary-0.3.0/src/lib.rs
new file mode 100644
index 00000000..b1ab8fcb
--- /dev/null
+++ b/vendor/cassowary-0.3.0/src/lib.rs
@@ -0,0 +1,623 @@
+//! This crate contains an implementation of the Cassowary constraint solving algorithm, based upon the work by

+//! G.J. Badros et al. in 2001. This algorithm is designed primarily for use constraining elements in user interfaces.

+//! Constraints are linear combinations of the problem variables. The notable features of Cassowary that make it

+//! ideal for user interfaces are that it is incremental (i.e. you can add and remove constraints at runtime

+//! and it will perform the minimum work to update the result) and that the constraints can be violated if

+//! necessary,

+//! with the order in which they are violated specified by setting a "strength" for each constraint.

+//! This allows the solution to gracefully degrade, which is useful for when a

+//! user interface needs to compromise on its constraints in order to still be able to display something.

+//!

+//! ## Constraint syntax

+//!

+//! This crate aims to provide syntax for describing linear constraints as naturally as possible, within

+//! the limitations of Rust's type system. Generally you can write constraints as you would naturally, however

+//! the operator symbol (for greater-than, less-than, equals) is replaced with an instance of the

+//! `WeightedRelation` enum wrapped in "pipe brackets".

+//!

+//! For example, for the constraint

+//! `(a + b) * 2 + c >= d + 1` with strength `s`, the code to use is

+//!

+//! ```ignore

+//! (a + b) * 2.0 + c |GE(s)| d + 1.0

+//! ```

+//!

+//! # A simple example

+//!

+//! Imagine a layout consisting of two elements laid out horizontally. For small window widths the elements

+//! should compress to fit, but if there is enough space they should display at their preferred widths. The

+//! first element will align to the left, and the second to the right. For  this example we will ignore

+//! vertical layout.

+//!

+//! First we need to include the relevant parts of `cassowary`:

+//!

+//! ```

+//! use cassowary::{ Solver, Variable };

+//! use cassowary::WeightedRelation::*;

+//! use cassowary::strength::{ WEAK, MEDIUM, STRONG, REQUIRED };

+//! ```

+//!

+//! And we'll construct some conveniences for pretty printing (which should hopefully be self-explanatory):

+//!

+//! ```ignore

+//! use std::collections::HashMap;

+//! let mut names = HashMap::new();

+//! fn print_changes(names: &HashMap<Variable, &'static str>, changes: &[(Variable, f64)]) {

+//!     println!("Changes:");

+//!     for &(ref var, ref val) in changes {

+//!         println!("{}: {}", names[var], val);

+//!     }

+//! }

+//! ```

+//!

+//! Let's define the variables required - the left and right edges of the elements, and the width of the window.

+//!

+//! ```ignore

+//! let window_width = Variable::new();

+//! names.insert(window_width, "window_width");

+//!

+//! struct Element {

+//!     left: Variable,

+//!     right: Variable

+//! }

+//! let box1 = Element {

+//!     left: Variable::new(),

+//!     right: Variable::new()

+//! };

+//! names.insert(box1.left, "box1.left");

+//! names.insert(box1.right, "box1.right");

+//!

+//! let box2 = Element {

+//!     left: Variable::new(),

+//!     right: Variable::new()

+//! };

+//! names.insert(box2.left, "box2.left");

+//! names.insert(box2.right, "box2.right");

+//! ```

+//!

+//! Now to set up the solver and constraints.

+//!

+//! ```ignore

+//! let mut solver = Solver::new();

+//! solver.add_constraints(&[window_width |GE(REQUIRED)| 0.0, // positive window width

+//!                          box1.left |EQ(REQUIRED)| 0.0, // left align

+//!                          box2.right |EQ(REQUIRED)| window_width, // right align

+//!                          box2.left |GE(REQUIRED)| box1.right, // no overlap

+//!                          // positive widths

+//!                          box1.left |LE(REQUIRED)| box1.right,

+//!                          box2.left |LE(REQUIRED)| box2.right,

+//!                          // preferred widths:

+//!                          box1.right - box1.left |EQ(WEAK)| 50.0,

+//!                          box2.right - box2.left |EQ(WEAK)| 100.0]).unwrap();

+//! ```

+//!

+//! The window width is currently free to take any positive value. Let's constrain it to a particular value.

+//! Since for this example we will repeatedly change the window width, it is most efficient to use an

+//! "edit variable", instead of repeatedly removing and adding constraints (note that for efficiency

+//! reasons we cannot edit a normal constraint that has been added to the solver).

+//!

+//! ```ignore

+//! solver.add_edit_variable(window_width, STRONG).unwrap();

+//! solver.suggest_value(window_width, 300.0).unwrap();

+//! ```

+//!

+//! This value of 300 is enough to fit both boxes in with room to spare, so let's check that this is the case.

+//! We can fetch a list of changes to the values of variables in the solver. Using the pretty printer defined

+//! earlier we can see what values our variables now hold.

+//!

+//! ```ignore

+//! print_changes(&names, solver.fetch_changes());

+//! ```

+//!

+//! This should print (in a possibly different order):

+//!

+//! ```ignore

+//! Changes:

+//! window_width: 300

+//! box1.right: 50

+//! box2.left: 200

+//! box2.right: 300

+//! ```

+//!

+//! Note that the value of `box1.left` is not mentioned. This is because `solver.fetch_changes` only lists

+//! *changes* to variables, and since each variable starts in the solver with a value of zero, any values that

+//! have not changed from zero will not be reported.

+//!

+//! Now let's try compressing the window so that the boxes can't take up their preferred widths.

+//!

+//! ```ignore

+//! solver.suggest_value(window_width, 75.0);

+//! print_changes(&names, solver.fetch_changes);

+//! ```

+//!

+//! Now the solver can't satisfy all of the constraints. It will pick at least one of the weakest constraints to

+//! violate. In this case it will be one or both of the preferred widths. For efficiency reasons this is picked

+//! nondeterministically, so there are two possible results. This could be

+//!

+//! ```ignore

+//! Changes:

+//! window_width: 75

+//! box1.right: 0

+//! box2.left: 0

+//! box2.right: 75

+//! ```

+//!

+//! or

+//!

+//! ```ignore

+//! Changes:

+//! window_width: 75

+//! box2.left: 50

+//! box2.right: 75

+//! ```

+//!

+//! Due to the nature of the algorithm, "in-between" solutions, although just as valid, are not picked.

+//!

+//! In a user interface this is not likely a result we would prefer. The solution is to add another constraint

+//! to control the behaviour when the preferred widths cannot both be satisfied. In this example we are going

+//! to constrain the boxes to try to maintain a ratio between their widths.

+//!

+//! ```

+//! # use cassowary::{ Solver, Variable };

+//! # use cassowary::WeightedRelation::*;

+//! # use cassowary::strength::{ WEAK, MEDIUM, STRONG, REQUIRED };

+//! #

+//! # use std::collections::HashMap;

+//! # let mut names = HashMap::new();

+//! # fn print_changes(names: &HashMap<Variable, &'static str>, changes: &[(Variable, f64)]) {

+//! #     println!("Changes:");

+//! #     for &(ref var, ref val) in changes {

+//! #         println!("{}: {}", names[var], val);

+//! #     }

+//! # }

+//! #

+//! # let window_width = Variable::new();

+//! # names.insert(window_width, "window_width");

+//! # struct Element {

+//! #    left: Variable,

+//! #    right: Variable

+//! # }

+//! # let box1 = Element {

+//! #     left: Variable::new(),

+//! #     right: Variable::new()

+//! # };

+//! # names.insert(box1.left, "box1.left");

+//! # names.insert(box1.right, "box1.right");

+//! # let box2 = Element {

+//! #     left: Variable::new(),

+//! #     right: Variable::new()

+//! # };

+//! # names.insert(box2.left, "box2.left");

+//! # names.insert(box2.right, "box2.right");

+//! # let mut solver = Solver::new();

+//! # solver.add_constraints(&[window_width |GE(REQUIRED)| 0.0, // positive window width

+//! #                          box1.left |EQ(REQUIRED)| 0.0, // left align

+//! #                          box2.right |EQ(REQUIRED)| window_width, // right align

+//! #                          box2.left |GE(REQUIRED)| box1.right, // no overlap

+//! #                          // positive widths

+//! #                          box1.left |LE(REQUIRED)| box1.right,

+//! #                          box2.left |LE(REQUIRED)| box2.right,

+//! #                          // preferred widths:

+//! #                          box1.right - box1.left |EQ(WEAK)| 50.0,

+//! #                          box2.right - box2.left |EQ(WEAK)| 100.0]).unwrap();

+//! # solver.add_edit_variable(window_width, STRONG).unwrap();

+//! # solver.suggest_value(window_width, 300.0).unwrap();

+//! # print_changes(&names, solver.fetch_changes());

+//! # solver.suggest_value(window_width, 75.0);

+//! # print_changes(&names, solver.fetch_changes());

+//! solver.add_constraint(

+//!     (box1.right - box1.left) / 50.0 |EQ(MEDIUM)| (box2.right - box2.left) / 100.0

+//!     ).unwrap();

+//! print_changes(&names, solver.fetch_changes());

+//! ```

+//!

+//! Now the result gives values that maintain the ratio between the sizes of the two boxes:

+//!

+//! ```ignore

+//! Changes:

+//! box1.right: 25

+//! box2.left: 25

+//! ```

+//!

+//! This example may have appeared somewhat contrived, but hopefully it shows the power of the cassowary

+//! algorithm for laying out user interfaces.

+//!

+//! One thing that this example exposes is that this crate is a rather low level library. It does not have

+//! any inherent knowledge of user interfaces, directions or boxes. Thus for use in a user interface this

+//! crate should ideally be wrapped by a higher level API, which is outside the scope of this crate.

+use std::sync::Arc;

+use std::collections::HashMap;

+use std::collections::hash_map::{Entry};

+

+mod solver_impl;

+mod operators;

+

+static VARIABLE_ID: ::std::sync::atomic::AtomicUsize = ::std::sync::atomic::ATOMIC_USIZE_INIT;

+

+/// Identifies a variable for the constraint solver.

+/// Each new variable is unique in the view of the solver, but copying or cloning the variable produces

+/// a copy of the same variable.

+#[derive(Copy, Clone, Hash, PartialEq, Eq, PartialOrd, Ord, Debug)]

+pub struct Variable(usize);

+

+impl Variable {

+    /// Produces a new unique variable for use in constraint solving.

+    pub fn new() -> Variable {

+        Variable(VARIABLE_ID.fetch_add(1, ::std::sync::atomic::Ordering::Relaxed))

+    }

+}

+

+/// A variable and a coefficient to multiply that variable by. This is a sub-expression in

+/// a constraint equation.

+#[derive(Copy, Clone, Debug)]

+pub struct Term {

+    pub variable: Variable,

+    pub coefficient: f64

+}

+

+impl Term {

+    /// Construct a new Term from a variable and a coefficient.

+    fn new(variable: Variable, coefficient: f64) -> Term {

+        Term {

+            variable: variable,

+            coefficient: coefficient

+        }

+    }

+}

+

+/// An expression that can be the left hand or right hand side of a constraint equation.

+/// It is a linear combination of variables, i.e. a sum of variables weighted by coefficients, plus an optional constant.

+#[derive(Clone, Debug)]

+pub struct Expression {

+    pub terms: Vec<Term>,

+    pub constant: f64

+}

+

+impl Expression {

+    /// Constructs an expression of the form _n_, where n is a constant real number, not a variable.

+    pub fn from_constant(v: f64) -> Expression {

+        Expression {

+            terms: Vec::new(),

+            constant: v

+        }

+    }

+    /// Constructs an expression from a single term. Forms an expression of the form _n x_

+    /// where n is the coefficient, and x is the variable.

+    pub fn from_term(term: Term) -> Expression {

+        Expression {

+            terms: vec![term],

+            constant: 0.0

+        }

+    }

+    /// General constructor. Each `Term` in `terms` is part of the sum forming the expression, as well as `constant`.

+    pub fn new(terms: Vec<Term>, constant: f64) -> Expression {

+        Expression {

+            terms: terms,

+            constant: constant

+        }

+    }

+    /// Mutates this expression by multiplying it by minus one.

+    pub fn negate(&mut self) {

+        self.constant = -self.constant;

+        for t in &mut self.terms {

+            *t = -*t;

+        }

+    }

+}

+

+impl From<f64> for Expression {

+    fn from(v: f64) -> Expression {

+        Expression::from_constant(v)

+    }

+}

+

+impl From<Variable> for Expression {

+    fn from(v: Variable) -> Expression {

+        Expression::from_term(Term::new(v, 1.0))

+    }

+}

+

+impl From<Term> for Expression {

+    fn from(t: Term) -> Expression {

+        Expression::from_term(t)

+    }

+}

+

+/// Contains useful constants and functions for producing strengths for use in the constraint solver.

+/// Each constraint added to the solver has an associated strength specifying the precedence the solver should

+/// impose when choosing which constraints to enforce. It will try to enforce all constraints, but if that

+/// is impossible the lowest strength constraints are the first to be violated.

+///

+/// Strengths are simply real numbers. The strongest legal strength is 1,001,001,000.0. The weakest is 0.0.

+/// For convenience constants are declared for commonly used strengths. These are `REQUIRED`, `STRONG`,

+/// `MEDIUM` and `WEAK`. Feel free to multiply these by other values to get intermediate strengths.

+/// Note that the solver will clip given strengths to the legal range.

+///

+/// `REQUIRED` signifies a constraint that cannot be violated under any circumstance. Use this special strength

+/// sparingly, as the solver will fail completely if it find that not all of the `REQUIRED` constraints

+/// can be satisfied. The other strengths represent fallible constraints. These should be the most

+/// commonly used strenghts for use cases where violating a constraint is acceptable or even desired.

+///

+/// The solver wil