Change answer <-> response matching in capa.get_submission_metadata
Add promise to ensure unit visibility is changed
New chapter on discussion features for all users
Check to make sure that the mysql service is running.
Create the test database if it doesn't exist.

There is a bootstrapping case where the test DB doesn't exist which causes reset_db to fail.
Merge pull request #4372 from edx/ahodges/documentation/discussionoverview

New chapter on discussion features for all users
Make text on register button on About page conditional.

 Added a new advanced setting; invitation_only

 If invitation_only display "Enrollment in this course is by invitation only"
 Otherwise, if outside of enrollment period display "Enrollment is Closed"

 This issue is logged at LMS-2670

 Also fixed in this PR is issue LMS-2717; even though the Register button was greyed out,
 clicking it sent one to the registration page.
Fix a bug in Individual Due Date Extensions (IDDE).

The IDDE implementation relied on a StudentModule being created for a
particular block in order to set the extended due date on that block.
Since StudentModules seem to be created on demand whenever data is
written to an attribute with Scope.user_state, it meant that if a
homework problem hadn't yet been touched by a student it was possible
that the due date extension wouldn't take effect for that problem, even
if the due date extension was successfully set for the parent unit.

This patch fixes this problem by creating new StudentModules as
necessary in order to make sure extended due dates propogate properly to
all problems in a unit.
Merge pull request #4418 from Stanford-Online/dcadams/make_registration_button_conditional

Make text on register button on About page conditional.
Merge pull request #4417 from edx/jbau/event-responsetype

Change answer <-> response matching in capa.get_submission_metadata
Disable test that is leaving modal open.

STUD-1963
Merge pull request #4430 from edx/feanil/fix_bokchoy

Feanil/fix bokchoy
Merge pull request #4435 from edx/christina/stud-1963

Disable test that is leaving modal open.
Merge pull request #4422 from edx/ammar/fix-handout-tests

Add promise to ensure unit visibility is changed
BLD-1190: Fix bok-choy test.
Remove LocMapperStore
LMS-2918
sql migrations cannot use loc mapper
Hotfix course_specific_reg/login for OpaqueKeys
Merge pull request #4413 from edx/remove-loc-mapper

Remove LocMapperStore
Remove warning filter from library code (should be set by applications/tests directly)