Fixing this issue, looks like this issue popped up when I pushed with the metadata form.
Added remove_unused_key_values.
When called, this removes any key values that aren't currently used by any image.

Also, did a little optimization on the metadata form code. Now it will rely on filling in old info through POST data rather than database queries.
Merge remote-tracking branch 'origin/upload-metadata' into upload-metadata

Conflicts:
	visualization/views.py