HubKit Refactoring for Testing

- Refactored wrapper library to favor composition over inheritance when it comes to AFHTTPClient. The library now owns an instance of an AFHTTPClient which can be changed and/or mocked. This allows for a bit more customization by separating the networking from the  api logic. Most importantly, it allows for testing of the api logic without needing network access.

- Added tests to verify some of the current API

- Lots of documentation. I started a new @endpoint comment to specify which endpoint the method talks to.