Push Notifications Addition

Review this. The functions work, but I don't have a copy of hanyuu to test it in a live/dev environment. Also, I didnt check the `Song().faves.api_keys()` part (or the database, really).

I've prepped the database ready for this. We also need a `DELETE KEY` function, and also a way to make hanyuu check if a person is registered. you do this using `/MSG NickServ STATUS <nick>`