Use the ID in the URL instead of the keyId in the payload

* The new ember-data removes the `keyId` attribute as part of the
  record normalization process
* The value of `keyId` is transfered to the `id` property
* By using the `keyId` in the payload we're breaking the semantics of
  the restful api, since the id *is* part of the URL
Update to Ember 1.0 and Ember Data 1.0 beta.1

* Refactor the code to use the new api in ember-data