Adding Nova Callbacks

Missing UTs (as Roaet calls them), but otherwise should be close to done.

DO NOT MERGE until unit tests are added...

^ ignore
Unit tests now added!
So I tried a few ways of doing this, but I'm not seeing a clean way of breaking this into separate functions. If ports and ipaddresses had logic in there, then that would be a easy place the break apart. However, with the only logic split being between (PUT,POST) and DELETE, I can't really come up with two methods that don't cause repeated code. Copy/Paste code always bothers me. I don't suppose you had a clearer picture in mind?