Merge pull request #1387 from edx/fix/vik/peer-linking

Peer grading linking issue
Merge pull request #1524 from edx/rc-peer-linking

Ensure that peer grading modules whose linked problem is removed change ...
Fix a couple pylint violations
Merge pull request #1526 from edx/zoldak/fix-pylint

Fix a couple pylint violations
Merge pull request #1483 from edx/diana/certs-upgrade-path

Verified Certificate Upsell
Merge pull request #1189 from edx/talbs/studio-cssarch

Studio: Revised CSS Architecture (resolves STUD-806)
Fix speed change bug.
Fix slider and pause bugs.
BLD-424. Update CHANGELOG.rst.
add user_id to tracking context

AN-213
update authors file
Merge pull request #1527 from edx/anton/video-speed-change-bug

Video player: speed change bug
Merge pull request #1478 from mulby/gabe/track-user-id

add user_id to tracking context
Disable multiple YT test due to flakinesss
Merge pull request #1528 from edx/will/disable-yt-js-test

Disable multiple YT test due to flakinesss
Merge pull request #1517 from edx/christina/delete-unused

Delete unused HTML templates.
BLD-205: fix total count.
Merge pull request #1522 from edx/db/fix-release-script

Fixes to release.py script
Update tabs.py
Update AUTHORS