Bunch of little best practice refactors

Bunch of tiny little tweaks

- `app.import` does the work of pulling a file into `assets/vendor.js` for you
- `ic-ajax` is slightly better behaved than `$.ajax` in terms of Promises and the run loop
- for Sass support just `npm install broccoli-sass --save-dev`

For animated route transitions, check out [ember-animated-outlet](https://github.com/billysbilling/ember-animated-outlet)