Restructured app.js
Added ember-data adapter, serializer and models for twitch.tv

This will replace the simple jquery ajax calls
Applied new ember-data models to routes
Refactored search model, route and controller.

* Applied ember-data models to search route
* Renamed localstorage model Searchbar to Search (the old Search model is now an ember-data model). The search history will now be saved under a new namespace (searchbar -> search)
* Simplified searchbar ordering
Removed old function for making twitch.tv API requests
Removed unused variable