PlaylistEditActivity: Fix artist listing.

This fixes a regression from 62b4bd3, apparently, Artist.EXTRA went one too far.
PlaylistEditActivity: Fix playlist edit listing.

This fixes a regression from 74d0b7f, one line deletion too far.
PlaylistEditActivity: Remove 2 static array initializations from a loop.
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
for "add artist" don't add full albums except for album artists

see #635
simplify volume bar listener

fixes #660
show track durations in current playlist