Add ember-cli add-on requirements

I've added the code necessary to make this work as an [ember-cli](https://github.com/stefanpenner/ember-cli) addon. 
Would you use broccoli to move it to some sort of tmp dir? I'm not sure how to go about that with the addon setup. Also it seems like the `app.tests` check isn't working. May need a hook for addons to add test files