Updates
- Allowed custom release types + handle more MusicBrainz secondary types in UI #373
- Subsonic API: returns the created/updated playlist in createPlaylist endpoint #393
- Subsonic API: added artist images in getCoverArt endpoint #392
- Subsonic API: added getTopSongs endpoint #365
- Subsonic API: set the cover art to be the one of the first track for playlists #388