*: use latest ffmpeg-sys using bindgen

* Update bindings to newest ffmpeg version for new ffmpeg-sys, which is mostly generated by bindgen
* Bring back removed feature flags
* Fix whitespace formating
* Remove prepended enum names to enum variants
* Remove unneeded allows

src/codec/audio_service.rs

@@ -1,4 +1,5 @@
 use ffi::*;
+use ffi::AVAudioServiceType::*;
 
 #[derive(Eq, PartialEq, Clone, Copy, Debug)]
 pub enum AudioService {