Attributes missing from Song/Album/Artist

[allerter]

Because of the get_full_info parameter in genius.search_song, we're not able to add all attributes to the Song object (e.g. album). Although they will be available from Song.to_dict(), it'd be nice to be able to access them as attributes. There are two ways to deal with this properly:

• Removing get_full_info altogether and update Song to have all fields.
  • advantages: Reduced complexity. No need to create and maintain two classes. Closer to the API if we discard the keys from genius.search_all and only stick to what genius.song gives us.
  • disadvantages: extra request to get the song info using genius.song.
• Breaking Song into two types: SearchSong and FullSong.
  • advantages: no extra request needed to get full song info if get_full_info=False.
  • disadvantages: Creating and maintaining two classes. SearchSong will have attributes from the Public/Web API.

I haven't taken a close look at search_album and search_artist, but the above could probably be said about those too.