Removed incorrect app_id filter.

The rest call already determined acl_access, and app_id is wrong in case
of shared assets.
Rewrite REST conflicts with Drupals User module usage of URLs.
By rblanker: Upgraded Drupal to 7.31.
Merge pull request #125 from arjenk/bugfix/asset-id-still

Your pull request has been merged, thank you Bro.