NowPlayingFragment: Check full path for null prior to extracting extension.
ArrayIndexerAdapter: Check for null prior to checking sorted for empty state.
use MPD's own database update time when checking for album cache

should fix cache update problems if the server's and the android client's
times are not synchronized, see #645
make backup of value before setting it
Jump to beginning of current song instead of previous if more than 5 sec have been played
Collapsed Albums: add setting
Collapsed Albums: add strings
Collapsed Albums: add PlaylistAlbum
Collapsed Albums: add size() and hasText() to AbstractPlaylistMusic
Collapsed Albums: add CollapsedPlaylistFragment
Collapsed Albums: use CollapsedPlaylistFragment
make playlist text autoscroll
make header in SongsFragment autoscroll
make Songs in SongsFragment autoscroll
autoscroll in albumfragment -- partially

Conflicts:
	MPDroid/src/main/java/com/namelessdev/mpdroid/views/AlbumDataBinder.java
show disc and track number in NowPlaying
fix regression of 686e8a2c9b4ac868d6b40d8c2d3cc3ba31b4e506

Album Artists were not listed
for "add artist" don't add full albums except for album artists

see #635
allow undefined album _or_ artist tag for "remove album"

but don't remove if both are undefined
fixes #631
simplify volume bar listener

fixes #660