more refined queue events + playlist delete binding

- move from listview to linearlayout + scrollview
- doesn't redraw the whole view on queue changes anymore
- uses new cursive functions for linearlayout (needs cursive git)

closes #3

src/events.rs

@@ -1,10 +1,11 @@
 use crossbeam_channel::{unbounded, Receiver, Sender, TryIter};
 use cursive::{CbFunc, Cursive};
 
+use queue::QueueChange;
 use spotify::PlayerState;
 
 pub enum Event {
-    QueueUpdate,
+    Queue(QueueChange),
     Player(PlayerState),
 }