Change answer <-> response matching in capa.get_submission_metadata
Add promise to ensure unit visibility is changed
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.
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.
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
Merge branch 'master_edx'