Brian Buch. changes
Users now have ownership over tags they've added to feed items.
Allow tags owned by a user to be deleted when attached to a feed item.
Add ability to change the ownership of a tag when modifying the filter.
Assign ownership of tags to user at the feed level.
Ignore some test helpers.
Add user ownership over hub tag filters.
Allow clicking on the username to show the tags owned by that user.
Merge pull request #24 from berkmancenter/3113

Issue 3113