Get CI set up

[aranasaurus]

It'd be really nice if we had some CI service hooked up to this thing so PRs automatically run the test suite before we merge them.

[codesman]

I just submitted #17 which fixes the Travis config for Xcode 8. Enabling TravisCI on GitHub is just a couple clicks away. I set it up on my fork and verified it works, I can do it here if you give me access...

[aranasaurus]

Thanks for getting this updated @codesman! I guess I completely forgot that we'd already had this set up long ago, hehe.

Fixed with #17 so closing!