devilry_qualifiesforexam.rest.aggregatedperiod: Documentation fix.
devilry_qualifiesforexam.models: Added a database model to store the information.

This will replace the old label-based approach.
devilry_qualifiesforexam.models: Database model to store the status.

And docs. See #304.
devilry_qualifiesforexam.models: Added a plugin field.

See #304.
devilry_qualifiesforexam: Document how plugins should work.

See #304.
devilry_qualifiesforexam_approvedornot: Skeleton.

See #304.
devilry_qualifiesforexam: UI skeleton.

See #304.
devilry_qualifiesforexam: Forward periodid to app.

See #304.
devilry_qualifiesforexam: Usable plugin system.
devilry_qualifiesforexam: Docs.
devilry_qualifiesforexam_approved: Renamed (removed ornot).
Merge branch 'master' of github.com:devilry/devilry-django