'Spotify' is now imported into the root module
Added Playlist 'fetch' method to  navigate playlist folders
Created new Playlist 'fetch' method to return full item metadata (renamed old method to 'list')
Playlist 'uri' property is now filled with the original request uri
Playlist 'fetch' now returns tracks (unless it's the rootlist)
'Uri' objects are now returned from Playlist.uri
Track 'albums' changed to 'album' (only one item is returned from protobuf)
Support for fetching the starred playlist
Added 'file_url' property to images
Fixed bug in Uri.to_gid()
SearchResponse totals are now converted to integers, minor fixes to descriptors and image objects
Fixed problem with Image.file_url
Added AlbumGroups (for Artists) and the Album 'is_available' and 'tracks' functions
Restructured protobuf object construction, Artist.albums now returns Albums (instead of AlbumGroups)
Fixed bug with type-specific searches
Initial stages of mercury (metadata) caching
Working (messy) mercury cache, needs to be restructured/cleaned up
Split hermes requests/caching into the 'spotify.hermes' module
Fixed bug in HermesCache.get
Fixed bug in HermesRequest.update_response, renamed some HermesCache functions