Limit Posts for Authors.

* 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).
Merge pull request #1 from rwjblue/limit-posts-for-authors

Limit Posts for Authors.