Add MetricsMixin back into DescriptorSystem and ModuleSystem

add more logging to grading

edx-val-Fix VAL error on re-import

Configuration error on course re-run

TNL 2098

Add CCX/IDDE configuration to yaml_config.py

Updates to the verify student Django admin.

Merge release to master

Clytwynec/split lms unittests into shards

Update translations (autogenerated message)

Update to the latest version of celery, and django-celery.

Ensure cohort management section has loaded.

* Ensure that VerificationStatus is append-only and immutable.
* Allow searching by student for verification status.
* Properly pluralize verification status.
* Use ConfigModelAdmin for ICRV config model admin.

Move location identifying strings into index (SOL-833)

Update in-course reverification XBlock SHA in requirements.

Conflicts:
	common/test/acceptance/tests/video/test_video_times.py

Update django-debug-toolbar-mongo to work with DJDT 1.x

TNL-2120, TE-849

The parent .cohort-management class was loading faster than its children (which makes sense). However,
flakiness existed on these tests because browser actions were depending on child elements that had not
painted yet.

Tested this using chrome with no X11 forwarding for extra speed. That exposed the ajax call
as well as the sub-class rendering issues.

When celery runs in eager mode, there is a bug and an exception
is not thrown when using retry logic. A PR to fix the bug can
be found here: https://github.com/celery/celery/pull/2607

In the mean time, we have to deal with the fact that in eager mode
celery will not throw the exception but simply return it. So we
raise it ourselves.

skip test that are causing incorrect pep8 reports in jenkins builds

Changelog for 3.1 can be found here:
  http://celery.readthedocs.org/en/latest/whatsnew-3.1.html

Changelog from 3.1.0 to 3.1.18 can be found here:
  http://celery.readthedocs.org/en/latest/changelog.html

Delete static_tab for split courses raises 500 error

Updated ora release tag.

ECOM-1476: sending email on software secure response initial work