merge in media-preview stuff

Squashed commit of the following:

commit 4087cee2f2a72bc2d3e44832809cbe99d25a3309
Author: rabite <rabite@posteo.de>
Date:   Tue May 21 20:40:27 2019 +0200

    rename to preview-gen

commit 275fd420a01c24393ae9cc07287204fde309130a
Author: rabite <rabite@posteo.de>
Date:   Tue May 21 20:30:50 2019 +0200

    update Cargo.toml and README

commit bf4c3fec0f8e0ff4628153297ac64fe165b4e443
Author: rabite <rabite@posteo.de>
Date:   Tue May 21 20:30:33 2019 +0200

    add config options for media

commit 3bf681cd078177d634507c51d04a45bdae184f1b
Author: rabite <rabite@posteo.de>
Date:   Tue May 21 13:46:00 2019 +0200

    always use unicode icons for play/pause/mute

commit ed2a0b31d1911e4d42086699ca1db636c327bacf
Author: rabite <rabite@posteo.de>
Date:   Tue May 21 13:04:11 2019 +0200

    rename to mediaview and some fixups

commit bda3f8f83bec07c3f52d06cf5f8eaad7fdbd85a0
Author: rabite <rabite@posteo.de>
Date:   Tue May 21 11:44:52 2019 +0200

    fix warnings

commit 9c917903cfa958b225f268ed4fb9f55f27162be0
Author: rabite <rabite@posteo.de>
Date:   Tue May 21 01:10:58 2019 +0200

    play audio through viedo widget

commit 9fe208b213710fae889f7701bdb3bf96d599c9a8
Author: rabite <rabite@posteo.de>
Date:   Tue May 21 00:15:12 2019 +0200

    fixed play when autoplay is off

commit d4036d52864d0a4e08f7da2cf6f7419ef070c1a9
Author: rabite <rabite@posteo.de>
Date:   Mon May 20 13:15:44 2019 +0200

    add icons for play/pause/mute

commit 29f0d203cfd7501b50d80501de146da9d89388bb
Author: rabite <rabite@posteo.de>
Date:   Mon May 20 12:26:53 2019 +0200

    add basic gif support

commit 8d28e4c23a91b0ef83739554c3a2f6671a9ff6f5
Author: rabite <rabite@posteo.de>
Date:   Mon May 20 11:43:57 2019 +0200

    fixed play after pause

commit 142017df78de77bcfffd8f3dd9612a06927e183b
Author: rabite <rabite@posteo.de>
Date:   Sun May 19 14:22:16 2019 +0200

    change to stale on drop

commit c0026c7f56f6a841df18e41bd1c9b33543e26cfb
Author: rabite <rabite@posteo.de>
Date:   Sat May 18 23:46:27 2019 +0200

    handle errors in gstreamer closure

commit ef37f872c54b9d21ed5505c2edb480c793afaef9
Author: rabite <rabite@posteo.de>
Date:   Sat May 18 23:40:24 2019 +0200

    add image-only mode to preview-gen

commit 15752464563463c6ecf892c1d8a14651bf32e1e5
Author: rabite <rabite@posteo.de>
Date:   Sat May 18 23:28:33 2019 +0200

    add copyright note

commit 4c9f08fc4de5d3bffefd42284b60aa81cfbae9f7
Author: rabite <rabite@posteo.de>
Date:   Sat May 18 23:27:30 2019 +0200

    make image/video previews optional

commit 9c2c2db2b20ecd4c30acbb1c77ad18c71f528c4c
Author: rabite <rabite@posteo.de>
Date:   Sat May 18 22:13:25 2019 +0200

    remove blank space under video

commit f7056d70fbe9147b3b95d7c10950653eadbb4f48
Author: rabite <rabite@posteo.de>
Date:   Sat May 18 22:06:49 2019 +0200

    remove dbg

commit cce820657ff1258cdb78d455dd3cf04564450cea
Author: rabite <rabite@posteo.de>
Date:   Sat May 18 21:50:25 2019 +0200

    added error handling to preview-gen

commit 80bbe15bacb99d1f4f97504a5d10ecf59544993f
Author: rabite <rabite@posteo.de>
Date:   Sat May 18 21:04:31 2019 +0200

    add time and visual seek bars to videoview

commit 4349945cc5549334f246be64bc7c8e2db43f9150
Author: rabite <rabite@posteo.de>
Date:   Thu May 16 22:39:19 2019 +0200

    fix sneaky process

commit 373128b7096d4de29924617e549a613a3aeea5b2
Author: rabite <rabite@posteo.de>
Date:   Thu May 16 22:07:27 2019 +0200

    fix out of controll processes

commit e061e065e913ab3923ffac1079a9f0a2be0df532
Author: rabite <rabite@posteo.de>
Date:   Thu May 16 20:51:56 2019 +0200

    add media_preview

commit f68c754895a9718d1a962980de9fbf02e5cb48cd
Author: rabite <rabite@posteo.de>
Date:   Thu May 16 19:37:04 2019 +0200

    beta image/video previews

commit 9a5460e553dd26ebccffaf819c64a8dc6ba74818
Author: rabite <rabite@posteo.de>
Date:   Tue May 14 20:36:25 2019 +0200

    external img preview

commit 3c4edfcb7611b36f6e537c73743e0b6bd269037b
Author: rabite <rabite@posteo.de>
Date:   Tue May 14 20:35:12 2019 +0200

    video preview

1 files changed, 8 insertions, 3 deletions

diff --git a/src/files.rs b/src/files.rs
index 17b2612..25e3393 100644
--- a/src/files.rs
+++ b/src/files.rs
@@ -18,6 +18,8 @@ use failure::Error;
 use notify::DebouncedEvent;
 use rayon::{ThreadPool, ThreadPoolBuilder};
 use alphanumeric_sort::compare_str;
+use mime_guess;
+
 use pathbuftools::PathBufTools;
 use async_value::{Async, Stale};
 
@@ -830,9 +832,12 @@ impl File {
         Ok((size, unit))
     }
 
-    // pub fn get_mime(&self) -> String {
-    //     tree_magic::from_filepath(&self.path)
-    // }
+    pub fn get_mime(&self) -> Option<mime_guess::Mime> {
+        if let Some(ext) = self.path.extension() {
+            let mime = mime_guess::get_mime_type(&ext.to_string_lossy());
+            Some(mime)
+        } else { None }
+    }
 
     pub fn is_text(&self) -> bool {
          tree_magic::match_filepath("text/plain", &self.path)