Switch to tracking improvements-and-fixes, add more spec coverage.

To keep from getting as out of date, I'm switching to tracking your improvements-and-fixes branch.

To avoid the next chunk of tests I write getting instantly outdated, any idea where you'll be targeting next?  

If you think you're pretty much done tweaking PullRequestsData helper, I could move on to that.

Otherwise, I was thinking the Github module, as that's smaller, but it sounds like you may be working more extensively there.