add admin ui support for constance keys as lists

fixes #54
Merge pull request #55 from IDCubed/master

add admin ui support for constance keys as lists
Use app framework for initializing in Django 1.7
Merge pull request #68 from jonasvp/django1.7

Use app framework for initializing in Django 1.7, refs #64
Merge pull request #1 from comoga/master

Push forward master