This adds support and integration tests for editing branch protection.

This includes all of the methods mentioned in this blog post:
https://developer.github.com/changes/2014-03-18-paginating-method-changes/
as well as a handful of others I found.  Sadly, this is a breaking
change for many of these methods because it changes the method
signature, but with yesterday's API change these methods are now broken
anyway. :(

Includes basic CRUD methods on repositories as well as listing branches
and tags.