add johnny module __version__ number  (PEP 396)
Fix breakage in django 1.6

sid happens to be None in one or more cases, just test it's not None before returning it.
Merge pull request #25 from artscoop/master

Fix transaction breakage in Django 1.6
Merge pull request #22 from dlam26/master

add johnny module __version__ number
Merge remote-tracking branch 'upstream/master'.
Hacks to make 1.6 work.