chore: Fix examples not working with `cargo run` (#998)

* chore: Fix examples not working with `cargo run`

## Motivation

PR #991 moved the `tokio` crate to its own subdirectory, but did not
move the `examples` directory into `tokio/examples`. While attempting to
use the examples for testing another change, I noticed that #991 had
broken the ability to use `cargo run`, as the examples were no longer
considered part of a crate that cargo was aware of:

```
tokio on master [$] via 🦀v1.33.0 at ☸️ aks-eliza-dev
➜  cargo run --example chat
error: no example target named `chat`

Did you mean `echo`?
```

## Solution

This branch moves the examples into the `tokio` directory, so cargo is
now once again aware of them:

```
tokio on eliza/fix-examples [$] via 🦀v1.33.0 at ☸️ aks-eliza-dev
➜  cargo run --example chat
   Compiling tokio-executor v0.1.7 (/Users/eliza/Code/tokio/tokio-executor)
   Compiling tokio-reactor v0.1.9
   Compiling tokio-threadpool v0.1.13
   Compiling tokio-current-thread v0.1.6
   Compiling tokio-timer v0.2.10
   Compiling tokio-uds v0.2.5
   Compiling tokio-udp v0.1.3
   Compiling tokio-tcp v0.1.3
   Compiling tokio-fs v0.1.6
   Compiling tokio v0.1.18 (/Users/eliza/Code/tokio/tokio)
    Finished dev [unoptimized + debuginfo] target(s) in 7.04s
     Running `target/debug/examples/chat`
server running on localhost:6142
```

Signed-off-by: Eliza Weisman <eliza@buoyant.io>

Signed-off-by: Eliza Weisman <eliza@buoyant.io>

1 files changed, 0 insertions, 70 deletions

diff --git a/examples/udp-client.rs b/examples/udp-client.rs
deleted file mode 100644
index 900d3616..00000000
--- a/examples/udp-client.rs
+++ /dev/null
@@ -1,70 +0,0 @@
-//! A UDP client that just sends everything it gets via `stdio` in a single datagram, and then
-//! waits for a reply.
-//!
-//! For the reasons of simplicity data from `stdio` is read until `EOF` in a blocking manner.
-//!
-//! You can test this out by running an echo server:
-//!
-//! ```
-//!     $ cargo run --example echo-udp -- 127.0.0.1:8080
-//! ```
-//!
-//! and running the client in another terminal:
-//!
-//! ```
-//!     $ cargo run --example udp-client
-//! ```
-//!
-//! You can optionally provide any custom endpoint address for the client:
-//!
-//! ```
-//!     $ cargo run --example udp-client -- 127.0.0.1:8080
-//! ```
-//!
-//! Don't forget to pass `EOF` to the standard input of the client!
-//!
-//! Please mind that since the UDP protocol doesn't have any capabilities to detect a broken
-//! connection the server needs to be run first, otherwise the client will block forever.
-
-extern crate futures;
-extern crate tokio;
-
-use std::env;
-use std::io::stdin;
-use std::net::SocketAddr;
-use tokio::net::UdpSocket;
-use tokio::prelude::*;
-
-fn get_stdin_data() -> Result<Vec<u8>, Box<std::error::Error>> {
-    let mut buf = Vec::new();
-    stdin().read_to_end(&mut buf)?;
-    Ok(buf)
-}
-
-fn main() -> Result<(), Box<std::error::Error>> {
-    let remote_addr: SocketAddr = env::args()
-        .nth(1)
-        .unwrap_or("127.0.0.1:8080".into())
-        .parse()?;
-    // We use port 0 to let the operating system allocate an available port for us.
-    let local_addr: SocketAddr = if remote_addr.is_ipv4() {
-        "0.0.0.0:0"
-    } else {
-        "[::]:0"
-    }
-    .parse()?;
-    let socket = UdpSocket::bind(&local_addr)?;
-    const MAX_DATAGRAM_SIZE: usize = 65_507;
-    socket
-        .send_dgram(get_stdin_data()?, &remote_addr)
-        .and_then(|(socket, _)| socket.recv_dgram(vec![0u8; MAX_DATAGRAM_SIZE]))
-        .map(|(_, data, len, _)| {
-            println!(
-                "Received {} bytes:\n{}",
-                len,
-                String::from_utf8_lossy(&data[..len])
-            )
-        })
-        .wait()?;
-    Ok(())
-}