Issue #61: Add currently playing track title and listen to phone state changes

Add the currently playing track title and also listen to phone state changes
on those devices that support it.  If it isn't supported and we don't have
the service then don't do anything.  If an incoming call occurs, pause the
currently playing track if any.
Issue #61: Add option to randomly play back tracks in an album

Selecting the Random icon will have playback randomly chose the next track
to play.