Fix bugs in play status and play pos notifications
Fix multiple issues with status notificatios:
* Playback state was not being sent when state wasn't sent
accompanying a metadata change
* Play state was being sent without an update
* Position was being sent without a change and with the wrong
indicator
* Position was not being scheduled for update when playing.
* Position was being scheduled for update when paused / stopped.
Bug:
30459664
Bug:
29400658
Bug:
28639383
Change-Id: Ic550dcab0430be45187b0267cc77875740388a2a