Orphan list bug

PT story: https://www.pivotaltracker.com/story/show/79488584

- Fixed all three bugs
- Introduced features to test the fix
- Introduced specs to ensure an orphan list can only be created for an active partner
- Introduced orphan_list factory
I know active admin throws everything into a single file and so maybe the distinction is less important. However, this feels like putting controller actions in the view to me.