Add UNSTARTED to PlayerState

See docs:
https://developers.google.com/youtube/iframe_api_reference

youtube/youtube.d.ts

@@ -150,10 +150,11 @@ declare module YT {
     }
 
     export enum PlayerState {
+    	UNSTARTED,
         BUFFERING,
         CUED,
         ENDED,
         PAUSED,
         PLAYING
     }
-}
+}