Bug fixes
- #368: Empty id in getCoverArt.
- #528: Saving playlists does not work.

Enhancements
- #514: Fix bugs in new image loader and make it default.
- #517: Cleaner separation of API result handling.
- #519: Better experience for new users.
- #520: Remove flash.
- #525: Properly generate the Video stream url, without actually making a request.
- #530: Use DiffUtil for better performance when refreshing the data.
- #532: Larger image cache.
