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>

vagrant:
  - check actual IP;
  - only init machine first time, just as native installations;
  - add .bash_profile to permissions fixup;
  - cleanup excessive newlines in making .bash_profile;

README:
  - include admin & debugging use;
  - info about re-initializing VM & manually running create-dev-env.sh;
  - add django admin & debug_toolbar setting info

Conflicts:
	AUTHORS
	scripts/vagrant-provisioning.sh

added namee to authors file

Added self to authors.

Conflicts:
	AUTHORS
	CHANGELOG.rst

Updated documentation in doc and README and made some small edits to bash script for added robustness

Added documenntation to the docs folder and edited the mac bash script in response to tests

Added largely functional bash script for setting up dev environment on macs. Due date of June 1st for open source deadline.