Teacher can edit students
remove stray settings after True
remove HttpResponseForbidden restriction on editing students (we just
disable the button for them)
oh look, i forgot to prepend test_* to my test names, hence they weren't
being run
change test_teacher_cant_edit_students to test_teacher_can_edit_students
Now Teacher can see only current unit and grade Unit Tests and Practise Tests
make sure we update the restricted teacher dynamic settings, as they may
change on the fly when running multiple test cases in a row, and we only
read the dynamic settings base class once
Merge pull request #2680 from aronasorman/allow_teacher_edits

Allow teacher edits
in test_exam_unset: make sure we're in the correct grade and unit
Merge branch 'nalanda-rct3' into student_testing_grade_unit_mapping
add the "show": true attribute to grade 3 students
Merge pull request #2681 from anuragkanungo/student_testing_grade_unit_mapping

Now Teacher can see only current unit and grade Unit Tests and Practise Tests
only show tests with attribute shown = True
Merge pull request #2688 from aronasorman/hide_tests

Hide tests based on show attribute
add grade attribute for tests
add unit attribute to tests
add unit and grade attribute on the test model
refactor teacher test filtering to use test unit and grade attribute
add test.show attribute
use Test.all as the standard attribute for accessing tests