Adds a new Email link to the instructor dashboard for frontend interface to send
email to course members. Adds a feature flag ENABLE_INSTRUCTOR_EMAIL to toggle this.
Creates a new djangoapp bulk_email that handles this action by getting the recipient
list and batching the emails to different celery tasks to do the actual sending.
Requires lynx package to convert HTML email to plaintext. Handles SMTP errors by
retrying or falling through to the next email. Adds the option to opt out of course
specific emails in the user dashboard with an Email Settings link for each course.
Uses severable configurable settings with defaults. DEFAULT_BULK_FROM_EMAIL
specifies the from address for email. EMAILS_PER_TASK specifies the number of emails
each celery task takes on. EMAIL_HOST, EMAIL_PORT, EMAIL_HOST_USER,
EMAIL_HOST_PASSWORD, and EMAIL_USE_TLS for the SMTP email backend settings.

Co-authored-by: Akshay Jagadeesh <akjags@gmail.com>

Studio JS fixture files no longer need individual symlinks

Fix the requirements in the sandbox instructions

Valera/fix empty captions panel no captions

Fixed 2 failing Jasmine tests. Removed unnecessary console.log() call.
Initializing of variables in a single var statement.

Now the captions panel will be shown with captions only after successful
retrieval of captions.

"There is a white panel over a non-youtube video."
When the captions file is not specified, we simply do not render the captions panel.

Keep comments in capa XML from causing failures

bugfix: Course static_tabs importing with display_name = "None"

Email Receipts and Billing Information

Integrate js-test-tool into testing infrastructure

Disable pylint violation E0611 when importing assert_* from nose.tools

Cleaned up files with muliline imports

Cleaned up files that do not use these imports

Misread comment

FIX: videosequence was not inheriting metadata, eg start date

Teach rake test tasks how to re-run failed tests

One time startup centralization

Use randomized mongo collection names in Studio tests

Crowdsourced Hints - "0.2 release"

collection names

Silence doc test errors/warnings

Inspired by: http://eldarion.com/blog/2013/02/14/entry-point-hook-django-projects/
Moves startup code to lms.startup and cms.startup, and calls the startup
methods in wsgi.py and manage.py for both projects.

Comments (and processing instructions!) are handled oddly in lxml.
This change will keep them from causing failures.  They will be omitted
from the HTML generated, which is fine, since they aren't needed there.

   Contains hotfix/2013-18-21

Fix/vik/oe state

Video Player: replace the description in the studio editing module for "subtitles" with "timed transcript"