Addressed the F2F issues for the spec:

- split the statechange event into three, one per state
- changed Promise<bool> connect() to Promise<void> changeState();
- replaced RemotePlaybackAvailability to the watch/cancel pattern;
- defined local and remote playback states and their relationship with the
  player state;
- specified the behavior around disableRemotePlayback attribute
- specified a little more about media resource selection for availability
  and remote playback
- updated the algorithms to reflect new terms