avoid NPE in Music.getPath()
remove albumartist user option and make getAlbums return merged lists
Go to Album Artist in NowPlaying
add albumCache and cachedMPD
replace MPD by CachedMPD (without enabling it)
enable cache
notify user about cache update failure
return AlbumArtists too in search results
add option whether to use local album cache
try to catch "listallinfo" errors in AlbumCache
allow AlbumsGridFragment for full album list when using cache
use constant and default to "true"