Add method to queue spotify tracks/albums/playlists/top lists/starred/artists

While it was already possible to add the spotify uri with #add_to_queue,
the metadata (artist, album, etc) would not be looked up by the Sonos device.
In order for this to be done we need to pass it a bit of DIDL metadata.
Merge pull request #26 from jasperla/add_queue_metadata

Add method to queue spotify tracks.