Merge pull request #7 from EVE-Tools/master

Updated for inferno12
Added production_time to InvBlueprintType
Merge pull request #8 from jenslauterbach/master

Added productionTime to InvBlueprintType
Added missing migration for the production_time field
Merge pull request #10 from jenslauterbach/master

Added the missing migration
Merge pull request #12 from EVE-Tools/master

Retribution Update
Updated migration so that it works with sqlite. Adding and dropping indices just does not work with sqlite. Should work with Django versions < 1.2. But didn't test.