Implement Disc interface
Created by: eonpatapon
A simple Disc interface to get the tracks of an album's disc.
You can get Dics instances from the discs property of Album.
eg: discs = Album(album_id).discs
For each Disc instance you have access to tracks and tracks_ids properties. Disc.tracks return Track instances.
eg: disc1_tracks = Album(album_id).discs[0].tracks