apps.core.search_indexes: Include parentnode long_name.
devilry_header: Adjust search styles.
devilry_search.rest.admincontent: Include assignment_id, and work with superuser.
devilry_search.tests.rest.base.HaystackTestSettings: Simplify and add warning.

Our approach did not force the use of a temporary search backend.
devilry_header...AdminSearchResultsView: Links to results.
devilry_header: Small changes.
devilry_header: Search links for examiners and students.
devilry_search.rest.base: Handle None in results.
devilry_search.rest.examiner: Include assignments.
apps.core.models.assignment: Added is_active(), including tests.
devilry_search.rest.examiner: Only return active assignments, and groups within active assignments.
devilry_search.rest.student: Only return published assignments.
devilry_header: Autoclose search menu when clicking a search result.
devilry_header: Autoclose search menu when clicking a search result - fixed.