PS: implemented mute/unmute for ring stream
PS: playbackStop on destroy
PS: moved stop logic out to playbackHalt
Added MediaButtonsReceiver
MBR: added register/unregister
MBR: added handleKey
PS: added action PlayPause
MBR: implemented handleKey
PS: split startCommand
PS: check if a track loaded before handling intents
PS: restructured notification building
DM: fixed getDanceFromUri with aliased dances
PS: (de)register MediaButtons receiver on audio focus events