Playlist implementation

Change-Id: I29ad26ccd3d55392612cbc3693a8254606f382b8
Playlist updates

Change-Id: I119986f499f9354882edf1c9f31ebaa9f47c311b
BackgroundThread refactoring

Change-Id: Iee4208051c2f8be6fb9748aa0ea4cb3e2853ecec
Implement SSOT for playing episodes

Changing the playing episode onCompletion caused a difference
in what the Activity thought was playing and the item actually playing.

Chose to use SharedPreference as the single source for what is playing.

Change-Id: Iee812f7f3d754dc4c01db6d3dbb35a2bb2902e8d