Create app with token

Replaces #8.

Refactor the user authentication to use Ember-Data instead of ad-hoc queries. The token is first fetched, either from the server with a user's credentials or from localStorage when the page reloads, then the adapter fetches a currentUser (if successful) or destroys the existing session (if a server request fails).

This also updated HAL-9000 to master for relationship support.