Use the GitHub API

[Uncommon]

Adding a GitHub account is implemented in Preferences, but nothing is being done with it, so something needs to happen there before 1.0.

Some ideas:

• Open a pull request
• Indicate which branches have pull requests (yours, other people's)
• Merge/close a pull request
• Set and indicate protected branches
• Branch status
• Commit status
• Explore forks
• Pull request for commit

[Uncommon]

https://github.com/p2/OAuth2 may be a good library for doing OAuth.