devilry_qualifiesforexam: Small changes.
apps.utils.groups_groupedby_relatedstudent_and_assignment: Helper for aggretion of group data for an entire period by student.
apps.utils.groups_groupedby_relatedstudent_and_assignment: Docs.
apps.utils.groups_groupedby_relatedstudent_and_assignment: Cleanup tests.
apps.utils.groups_groupedby_relatedstudent_and_assignment: Decoupling of querysets and docs.