Disable migrations by default in python unit tests

Merge release -> master for release-2016-10-12

Rendering model states when running migrate in Django 1.8 consumes
on the order of 4x-6x more memory than <1.8.

References:
* https://code.djangoproject.com/ticket/24745
* https://code.djangoproject.com/ticket/24743

This is causing failures in Jenkins as the workers run out of memory
and either processes cannot fork or the Out Of Memory Killer
kills a process that is running tests.

Disabling migrations until we do either or both of these:
* Upgrade to Django 1.9 and turn them back on. See EV-92 "Discovery: Upgrade edx-platform to Django 1.9"
* Address TE-1310 "Unit tests should be able to run without migrations"

Sstudent/hack instructor task

Grading Policy endpoint in Grades API

Release Candidate rc/2016-10-12

This copies the grading policy endpoint currently in the
course_structures django app to its new location, in preparation
to remove the old app.

TNL-5701

update all references to instructor module

Move student.views to student/urls.py

Move session_inactivity_timeout to openedx/core

Merge pull request #13633 from edx/shr/bug/TNL-557-conditional-module-children-modules-empty-context

Fix empty context KeyError for conditional module

Fix Reverted: Have DiscussionXBlock take care of loading JS and CSS files it depends on

Move header_control from common to openedx/core

Corrected issue with the Show Hint button enabled state with single hint.

Move contentserver to openedx/core

TNL-5737

Bookmarks button style fix

Move audit_log utility function to openedx/core

Upgrade django-oauth2-provider to 1.1.4

Dump to neo4j updates plus signals

* Add openedx.core.lib.xblock_builtin.get_css_dependencies and get_js_dependencies,
  which respect PIPELINE_ENABLED setting when determining dependencies.
* Move new discussion-related Sass files into discussion subdirectory.
* Use "load_unicode" instead of "render_template" to load JS to add to fragment for DiscussionXBlock.
* Remove unused "course" parameter from context for DiscussionXBlock.student_view.
* Add RTL stylesheet for DiscussionXBlock, and enable the block to load correct stylesheet.
* Load MathJax only once, and include code for configuring MathJax in discussion bundle.
* Make sure username renders correctly in DiscussionXBlock response header.
* Move WYSIWYIG Markdown editor styles to _build-discussion.scss.
* Remove unnecessary import of discussion/utilities/v1-compatibility from _build-discussion.scss.
* Keep courseware-chromeless.html in sync with courseware.html.
* Load CSS for discussions on Teams tab.  This makes it possible to remove CSS for discussions from Sass files for "Course" tab.
* Load js/src/tooltip_manager.js, jquery.autocomplete.js and jquery.autocomplete.css on "Course" tab.

Add ui in studio for conditional_module.

Fixing issues with photo verification flow

improvements to the command line interface for caching

User Menu Added Role information missing from menu items

Show verification expiration message on learner dashboard and allow them to reverify if expiration is X days away.
ECOM-2979

Change CCX coaches to have staff role on CCX courses.

Add UTM tracking for registrations

comparison should be case-insensitive

Move datadog from common to openedx/core