Add pagination to asset retrieval
and push sorting down to the query
Use HTTP header for comments service auth

Previously, authentication was done using a URL parameter, which would
appear in various logs. Now, authentication is done more appropriately
with an HTTP header. Note that this requires cs_comments_service commit
cf39aabdd160176ebf206ca19d3ee030161a0b47 or later.
Test 100 assets w/ pagination
Add EmptyDataRawDescriptor.
fix instructor dashboard grade export for specific assignment
add comment - instructor dashboard grades fix
Merge pull request #1348 from edx/dhm/bug_publish

Delete on publish to prevent orphans
Pass student grade label to certification process
Check that email subtasks are known to the InstructorTask before executing.
Move logic that decides whether to show shoppingcart to middleware

Middleware is a better place for this, rather than navigation.html
template
pep8 + pylint
Enable and update bulk email acceptance test
wait to load video module until YT API is ready
Mock YT.ready in Xmodule JS tests

and disable tests that fail for unrelated reasons
Remove references to onYouTubePlayerAPIReady and onHTML5PlayerAPIReady
Rebased. Updated Jasmine describe messages to make them more clearer.
Enabled 2 disabled Jasmine tests. Fixed them.
Remove outdated comment
Enabled 2nd disabled Jasmine test.
Work in progress.