Add unique together constraint on AvailableMission
Check multiple unlock_title

Refers to #77 but can't reproduce.
Migration for unique available mission
Add avg_folks (fix #75)
Add default to None for ScriptField
Add unique slug for title
Use slug in title scripts
Migrate to null kingdom
Do not delete children and pupils with a Folk
Merge branch 'master' into bargain
Admin for bargain
Travis test

Remove syncdb and migrate, since test should do this too.