Remove some outdated code.
added and updated pavelib/quality.py from dglance branch, deprecated rake quality tasks
fix for pylint/pep8 defaults
i18n: Make XBlock buttons & components have localizable display names

1. Current code uses type name as the display names for XBlock buttons, so the name of these five buttons can't be localized. This fix contains code that adds a 'display_name' field for the buttons, and makes their names localizable.
2. The display names of components in advanced, html and problem types can be localized now.
i18n: Fix an i18n string extraction error in 02_html5_video.js

Replace a string concation to a single string to prevent the partial extraction of the string.
BLD-967: Fix regExp.
Bok-Choy Tests for Video Start Time, End Time and Finish Time
Merge pull request #3883 from edx/anton/fix-youtube-regexp

Fix youtube regular expression in video player editor
BLD-975: Remove Video player outline.
Merge pull request #3694 from edx/ammar/bok-choy-video-time-tests

Bok-Choy Video Time Tests
Merge pull request #3876 from louyihua/localization-fix-video

i18n: Fix an i18n string extraction problem in 02_html5_video.js
Merge pull request #3877 from louyihua/translation-fix-cms

i18n: Make XBlock buttons & components have localizable display names
Merge pull request #3886 from edx/diana/clean-up-outdated-files

Remove some outdated code.
Merge pull request #3885 from edx/anton/fix-video-outline

Remove Video player outline.
Add some missing AUTHORS
Make SPOC gradebook an API implementation

rather than just hacked in to the instructor_dashboard base file.
Also move the tests from the legacy implementation to the new dash API implementation.
Remove gradebook code from legacy.py (moved to instructor/views/api.py)
Redirect most studio access through draft modulestore
rather than have caller figure out whether to call draft or direct.
Fixes get_children to always find draft children in studio.
STUD-1662
Merge pull request #3887 from edx/ned/add-authors

Add some missing AUTHORS
Merge pull request #3868 from edx/sarina/inst-dash-cleanup

Make SPOC gradebook an API feature