Post Travis build status to #hound

* Notify on build failure
* Notify on first success after previous failure
When I encrypted the token with `travis encrypt`, it touched up the `.yml` file itself.

Oddly enough, it indented all the array lines all the way to the left, which I had to manually bump back out. 

I'm all for following convention, but it seems that the `travis` gem has its own idea of the conventional layout, and we're going against it.