Incremented diff cover version to fix 100% coverage bug.

Updated acceptance tests to match new behavior in video captions.

Unanswered on input

Jbau/bulk email faster tests

Adam/calc refactor

Move mitxmako initialization to a startup module

Upgrade newrelic agent to the latest version

Kill processes after running rake

Instrument course email for DataDog

Small change to email registration template

Affects:
Choicegroups, option inputs, textline, and formula equation inputs

Rewriting of links for Course Updates and Course Handouts.

    Added some text to guide the student to register with a particular email address.
    This is the one that was entered into the enrollment/invitation form by the instructor.
    Modified the template and associated test.

Properly display student progress

Remove network calls in test suite

STUD-669.

Course email for instructors

Adds the edX Marketing-approved template as html default.

Includes Data + Schema migrations for optout email -> user.id change.
Note that migrations should be reversible.

Some minor pep8 cleanup

Switch to using decorators; refactor and cleanup tests.

 Delay for possible race condition with fetching course email object.
 Use settings.SITE_NAME for host name to generate email footer url.