devilry_gradingsystem.views.admin.selectplugin: Logically usable.
devilry_gradingsystem.views.admin.selectplugin: Save selected plugin id.
devilry_gradingsystem.views.admin.selectplugin: More foolproof UI.
devilry_gradingsystem.templates...django_formerrors_as_alertboxes: Reusable error handling template.
devilry_gradingsystem.views.admin.selectplugin: Use form and handle errors.