* Ensures that posts listing only shows posts that the current user
authored, if they only have the Author role.
* Do not transition into the posts.post route if the current user is
not the author (but has the Author role). This is needed because
the API server will always return the post (regardless of the current
user).
closes#2998
- update PostSerializer to use DS.EmbeddedRecordsMixin
- create PostAdapter to include include=tags in query params for POST and PUT
- set include=tags for various GET post requests
- change PostModel to have { embedded: always } instead of { async: true }
- update Ember-Data to beta8 from beta7
- make call to get tags from model in editor.edit route synchronous since the tags now exist in the store
- change casper test to wait for call to posts api with `?include=tags`
closes#2947
- make a PostSerializer to embed the tags objects in the posts POST/PUT request
- on editor save, clear out tags from the post and data store that have `id: null`
