Added lots of comments for order statuses
Removed deprecated, test related content
Removed deprecated code
Sorted imports in alphabetical order
Use constants
Added support for subject specific special arrangements
Fixed amount_for_x, which caused extra materials to appear in pre-filled order forms
Fixed imports
Created new decorator for permission checking
Use SchoolPermission decorator
Import SchoolPermissions decorator from education app
Use context['school'] from SchoolPermission
Fixed references to sites