Specify a different xcontent mongo db for the acceptance tests

Don't mention edge in the subject line; use same message for edx and edg...

Cleanup before adding external grader

Updated diff-cover to version 0.1.3 to fix a bug

Jonahstanley/make units parallel

Refactor a bit modx_dispatch

Update CHANGELOG for per-student problem rescoring.

Call event.preventDefault() on notification action buttons

But allow you to specify that the event should not be prevented

Fix unicode for errors on capa problems

removes choiceresponse wiping after clicking Show Answer

Enable per-student background tasks.

Fix acceptance tests expecting outdated CSS.

Refactor Advanced Settings page to use Backbone notifications.

Backbone notifications secondary actions

Change width of labels for multiple-choice capa problems to width of text, not 100%

Handle secondary actions on notifications either specified as a single object,
or as a list of objects. Under the hood, the initialize method converts a single
object to a list containing a single object.

Ned/pylint fixes

Previously the "saved" view was never hidden, even after more data was
edited. So if one field was saved successfully and then another was
not, we would find ourselves in the unfortunate situation of seeing
both views at once, leading to much confusion.