initial lockscreen / notification controls implementation
need to fix:
- initial hook when the app is first started
- fix play/pause from lockscreen
- add controls and customize the notification
- test, and fix bugs
now hooks up when the app is first started
fixed play/pause icon in notification
code cleanup & fixed remote client update
fixed some stuff with notification and remote control
added album/track cover to notification and remote control client
added expandable notification
Backwards compatibility down to API level 14. Not tested.
Remove useless files
Reindent layouts
Center the small notification
Much better big notification
Removed annoying toasts
Notification: Sync the headers with the rest of the project headers.
X button should close the notification and not stop MPD
MusicService locks the connection as long as it is running. Will be configurable later
Previous button should go to previous song, not rewind :)

We should do a previous if < 5sec, rewind otherwise but I'm just restoring the old MPDroid behaviour
Revert changes to NowPlayingFragment (it should stay independent of the service)
Idea stuff
Remove unneeded mainmenu entries
Rename MusicService to NotificationService, better fitting its future role.