RompR 0.40

It's been a while but RompR 0.40 is ready.

The docs will be updated in due course but until then here's a summary of the changes:

1. New information panels to get info from MusicBrainz and Discogs, and also a File Information panel.
2. Rewritten album art manager now allows drag-and-drop, and will search Last.FM, MusicBrainz, Discogs, and Spotify.
3. Mobile version now has a volume control.
4. Mopidy Users: SoundCloud information panel gets information about the current SoundCloud track (when used with the Mopidy-SoundCloud backend)
5. Users of Mopidy-Beets backend can create an albums list using this backend. This permits RompR to use album art downloaded by Beets, and also to display song lyrics.
6. Support for Mopidy's HTTP frontend - which gives better playlist management and much improved search capabilities (enable by accessing /rompr?setup)
7. Albums can be sorted by Date - but note that date tagging may not produce the results you expect unless you use 'Original Release Date' as your 'Date' tag (Beets can do this for you)
8. Podcast support - stream and download podcast epsiodes. Automatic removal of expired episodes, automatic updating of podcasts, all kinds of stuff.
9. Probably loads of other stuff I've forgotten about