(SOL-835) Addressing flakiness of the reindexing bokchoy acceptance test

Add feature flag to allow hiding the discussion tab for individual courses.

Merge release into master

Conflicts:
	cms/djangoapps/contentstore/views/course.py

MIT CCX: Use CCX Keys

Prevent duplication of tabs with different names.

Make addCleanup idempotent.

Update translations (autogenerated message)

only require ccx-keys once

get_current_ccx will now expect a CourseKey instance as its argument, and will raise a value error if this expectation is not met.

document reason for local import

add special methods to pass attribute setting and deletion through to the wrapped modulestore

add __setattr__ and __delattr__ per code review, update __init__ to work with new methods

style change per code review

clean up context manager usage as recommended by code review

remove unused code and imports

convert modulestore type tests to use the `get_modulestore_type` api, remove unused imports

code quality: add docstrings

increase coverage for utils tests

fix bug found in testing.

increase test coverage on modulestore wrapper

code quality fixes

code-quality: ignore import error, but mark site for future consideration

ECOM-1724 a11y footer updates

First draft.

Fix flaky lettuce test. TNL-1452

In bulk_operations() exit, emit signals at the end.

* Add action text to social media links.
* Make the alt text for mobile links more descriptive.

Course Blocks + Navigation API (feature flagged) for Mobile

[LTI Provider] Basic LTI authentication

Avoid POSTing unnecessary payment processor parameter

Release

Sometimes this file does not exist depending on when a test failed. Remove it gracefully.

This is an initial authentication implementation that allows LTI users to
log in transparently to edX. The behavior is driven by pilot users at
Harvard; this was the most requested feature.

The patch creates a new database model that maps users' LTI identifiers
to newly-created edX accounts. If an LTI launch comes in with a user_id
field that is not in the database, a new edX account is created with a
random user name and password. This account is then stored in the
database, so that it is permanently associated with the LTI user ID.

This patch takes a simplistic approach to session management. If a user
is logged in with a different account when they perform an LTI launch,
they will be logged out and then re-logged in using their LTI account.

In order to keep the patch simple, I have split out some refactoring
that needs to be done into a separate branch that I'll post once this
has been merged. Since we no longer redirect to the login page, we don't
need to maintain two separate LTI endpoints (one for the LTI launch and
one for authenticated users), or deal with the session management that
requires. There are also multiple fetches of the LtiConsumer object
(one in the view, one in the signature validation) that the later
patch will consolidate into one.

This branch fixes the previous conflicts with the test refactoring
carried out in PR 8240.

Specified number of mongo and split calls in xblock outline handler test with ddt.

Merge pull request #8495 from edx/shr/bug/tnl-2122-fix-show-enable-import-from-youtube-transcript-button

add name param check_transcripts

Patch/2015 06 11

PLAT-674

show credit eligibility requirements in studio

ECOM-1591

remove references to middleware that were missed previously

use key apis rather than local implementation of key conversion.  remove local implementationa

remove spurious test for attribute

fix test setUp to avoid unneeded flattening

code quality fixes

add security check ensuring that the coach is coach for *this* CCX.

prevent ccx/deprecated course id problems

1.  do not allow ccx objects to be created if the course id is deprecated
2.  filter out any ccx memberships that involve deprecated course ids (in case there are bad ccxs in the database)

Fix test failures and errors arising from incorrect code path execution

Create context manager to handle unwrapping and restoring ccx values for the modulestore wrapper, employ it throughout modulestore wrapper implementation