remove instances of @edx.org email addresses in our default settings

Bug: LMS-1363
BLD-205: fix total count.
Make export URL restful.

STUD-846
Improve accessibility of forum follow buttons

They now include screen reader-friendly text, have the ARIA checkbox
role, activate on keypress (for space or enter), and occur in the DOM
after the header information (title, etc.)
Merge branch 'release'
add error handling for update_score for OEE when no child_history
Merge pull request #1513 from edx/anton/word-cloud-total-count-in-studio-bug

Anton/word cloud total count in studio bug
Implement background email tasks on student dash

LMS-1244
Fix AssertionErrors that were raised when creation of an XModule failed

The ErrorDescriptor wasn't getting the appropriate xmodule_runtime set,
and thus immediately raising an AssertionError when we tried to retrieve
and _xmodule from it.

[LMS-1388[
Merge pull request #1558 from edx/sarina/beta_email_background_history

Implement background email tasks on student dash
Remove label from forum posts by global staff

The motivation for this change is performance. The forums UI code gets
the list of users for each role and renders the staff label based on
those lists. The list for the staff role is expensive to compute because
there is no index on the is_staff attribute, and we cannot create one
because the User model is built into django.

Users with is_staff=True are still assigned the Moderator role upon
enrolling in a course, so this change will have no practical effect
except that a user who is granted staff privileges after enrolling in a
course will have to be made a Moderator in order for their posts to be
labeled.

Additionally, the UI did not use the list of users with the Student
role, so that list has been removed as well.
Course id clash command
Allow 'course' as course's id keyword
Skipping new test until Jenkins mongo updated to >= 2.2
Added wait for problem to re-render when checking or resetting it
Added wait for JS on upload page
Fixed an issue where css_click wasn't waiting for JS to load
Merge pull request #1484 from edx/dhm/course_id_clash

Course id clash command
Merge pull request #1568 from edx/will/acceptance-test-fixes

Will/acceptance test fixes
Studio: revises the styling for the export view to sync with the import view's UI
Merge pull request #1553 from edx/gprice/forum-follow-a11y

Improve accessibility of forum follow buttons
Merge pull request #1561 from cpennington/hotfix-assertion-error

Fix AssertionErrors that were raised when creation of an XModule failed