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"
gzip-compress album cache file
don't save all track times to cache, only save number of tracks
make gzip optional and disable it