Fix message.
i18n: Make .underscore files translatable

Currently the strings in .underscore files are not extracted
by i18n/extract.py, which causes most strings in such files
are not translatable. As there is no existing tools which can
extract messages from these files, a simple shell command is
written to do such job.
Add note strongly recommending .webm and .mp4 video format
BLD-724: ChoiceTextResponse i18n.
Fixed staff debug info endpoints for staff member.
LMS-2737
Merge pull request #3852 from edx/waheed/lms2737-fix-staff-debug-info-links

Fixed staff debug info endpoints for staff member.
Fixed links for units loaded via ajax.
LMS-2711
Merge pull request #3755 from edx/waheed/lms2711-staff-debug-links-fixed-for-all-units

Fixed links for units loaded via ajax.
Bok-Choy Video Tests Batch9
Merge pull request #3895 from edx/anton/i18n-choice-text-response

BLD-724: ChoiceTextResponse i18n.
Merge pull request #3946 from edx/anton/i18n-code-response

CodeResponse: fix i18n.
Diacritic Plugin for Annotator TooL: Added CSS and JS files

- UI Fixes for Diacritic Mark Plugin
Diacritic Plugin for Annotator Tool: Added studio input
Diacritic Plugin for Annotator Tool: Pull-request Fixes

Making sure extension comes after annotator css
Fix typo
Merge pull request #3938 from edx/sylvia/docs/BLD-1049

Sylvia/docs/bld 1049
Merge pull request #3480 from lduarte1991/lduarte-harvardx2

Annotation Tool Clean up and Plugins
Merge pull request #3704 from louyihua/localization-fix

i18n: Make .underscore files translatable
Merge pull request #3682 from edx/ammar/bok-choy-video-tests-batch9

Bok-Choy Video Tests Batch9
Check YouTube for Bok-Choy