secure-cookies: Allow to use secure HTTPS cookies (Django setting)

Cf https://docs.djangoproject.com/en/1.4/ref/settings/#std:setting-SESSION_COOKIE_SECURE
Make code more robust to bad input (for case where DB was populated with string None)
Increase randomness of course name in testcase
Displaying Insights Link for All Instructors
Click on posts I'm following should load threads

When as course moderator when we click on posts
I'm followng from sidebar dropdown it gives error
that threads cannot be loaded. It should show all
the threads the user is following.

TNL-469
Remove unimplemented grade_summary feature.
Add molecule viewer tool to Exercises and Tools section
Merge pull request #5273 from edx/sylvia/docs/DOC-759

Sylvia/docs/doc 759
TNL-272: Fix double loading of cms-modules.js.
Merge pull request #5388 from mlkwaqas/waqas/tnl469-error-loading-following-threads

Click on posts I'm following should load threads
Merge pull request #5401 from edx/insights-for-all

Displaying Insights Link for All Instructors
Merge pull request #5290 from mitocw/bdero/fix-grade-summary-opaque-keys

Remove unimplemented legacy dashboard grade_summary feature
Converted annotation lettuce test into bok-choy test.
TNL-353
add couse key verification decorator in common for use in both studio and lms
PLAT-88
Merge pull request #5404 from edx/waheed/tnl353-wrote-annotation-bok-choy-test

Converted annotation lettuce test into bok-choy test.
Merge pull request #5362 from edx/zub/bugfix/plat-88-importstatusinvalidkeyerror

add couse key verification decorator in common for use in both studio an...
Merge pull request #5393 from edx/anton/js-double-loading-studio

Fix double loading of cms-modules.js.
Only execute regex queries for case-insitive lookup in split.

[LMS-11402]
Merge pull request #5396 from cpennington/split/specialize-regex-for-case-insensitive

Wrap get_item in bulk_operations to limit the number of queries for course structure.
Fix BulkAssertionMixin so that it actually asserts the truth/falsity of the contained assertions