Allows you to create a nice music player with all the trimmings, including: * up to 5 actions in the bigContentView, styled as transport control buttons * up to 2 of those actions in the 1U (!) * a nice custom progress bar * a tinted background (taken from your Notification.color) * a special place to put your MediaSessionToken Bug: 15147533 Change-Id: Ic20a2b369eb6c5fe4853987a44ffd9bace720c7f