Add application singleton
Use application singleton to avoid crashing
Use the application singleton a lot more
Make AlbumsFragment use the albumartist tag as set in the options
The preference for album grid decides if it should be a list or a grid. No more cache based decision.

We can't detect MPD's version to decide if we can show the grid since we're probably not connected yet.
Add album grouping support on MPD 0.19
Fix wrong attributes set. Still not everything working
Fix album details listing adding useless albumartist parameter. If album listing regresses, REVERT THIS
Use albumartist only for MPD 0.19+ album listing. It's the only setting that makes sense anyway.
Add a way to log every sent mpd command (disabled by default, BuildConfig.DEBUG does not work in libraries)
MPDStatus: Pattern match using precompiled regular expressions.
NotificationService: Make service persistent to option.

If NotificationMode is started, don't unselect it. Keep the service open,
unless the user opts to hit the close button.

Rather than update on track change, update on playlist change. This will be
more granular and it will include stream information updates unlike track
changes.

Finally, this patch turned out to be a small refactoring, so there are
many changes not targeted by the description.

For more information about how persistent notification works:
https://github.com/avuton/dmix/wiki/How-the-services-work-in-MPDroid
NotificationService: Fix warnings.
StreamingService: Warning fixes.
RemoteControlReceiver: Warning fixes.
NotificationService: When the play state is paused, don't send pause command.

This works around an MPD bug, if MPD is paused some versions will toggle to play.
StreamingService: Prevent a MediaPlayer crash if stream halts during buffer.

MediaPlayer can cause an ANR or crash (depending on its state) if the stream
is stopped during buffer and the object is reset or released. Workaround that
by not resetting or releasing during buffering. The disadvantage to this is
that next start we may have some stale bits in the buffer which we'll hear
first, then it'll rebuffer.
Music.java: Refactor the constructor.
MPDStatus: Fix warnings.
MPD.java: Remove duplicate response parsing.

Many tag lists are parsed the same exact way, eliminate this duplication and
clean up the method it uses to parse it.