Implement media type.
Merge branch 'develop' into media_type
Check for the existence of a media record. Add the media view helper.
Pass media representation to view helper.
Add media API resource.
Add media to item representation. Correct item reference in media representation.
Merge branch 'develop' into media_type
Render from media representation.
Merge branch 'develop' into media_type
Remove redundant view helper.
Inject service manager into select view helpers. Use correct exceptions in media view helper.