feat: video publishing (#42)

- Prepare webrtc abstraction ( for future wasm support )
- Added track publish support for videos
  - Added LogoTrack example to simple_room demo
- Lot of cleanup
- There are compiler warnings I'll solve on our v1 release

livekit/src/lib.rs

@@ -1,12 +1,9 @@
 extern crate core;
 
-pub mod proto {
-    include!(concat!(env!("OUT_DIR"), "/livekit.rs"));
-}
-
+pub mod proto;
+mod room;
 mod rtc_engine;
 mod signal_client;
-mod room;
 
 pub mod webrtc {
     pub use livekit_webrtc::*;