Lastfm (Song): Port to new spice api

@jagtalon I dont remember, but i think we used tags in some ia, was thinking perhaps we could add those here. (didnt put image, didnt seem very relevant).
SS below: -
![lastfmsong](https://cloud.githubusercontent.com/assets/1424236/5238576/2e86ec74-78e0-11e4-9c85-d21f8d73649e.png)