Mgmt commands to clear data from historical tables.

[ENT-685] Bump edx-enterprise to 0.52.2.

include upsell messaging in the 10 day nudge emails

mattdrayer/ENT-698: Log additional context for SuccessFactors errors.

fix flaky throttling test

[ENT-643] Bump edx-enterprise to 0.52.1.

Flag for Hours of Effort in course certificates

Block completion model

Retrieve different data fields from Discovery

Clean up dashboard_certificate_information template.

* Includes custom manager.
* Includes percent validation.
* Includes useful indices.
* Subclasses TimeStampedModel

OC-3086

Don't send RET emails after course end

Use singular getter function where only one requirement is expected

Fix program marketing page to assume less (fix 500 error on stage/prod)

Fix quality issues to get green build for master.

Video transcript preferences

Course dates web fragment for mobile apps.

Implement a course dates fragment as a web view, currently we are using
the course info page to get the course dates section by parsing the
whole html page.

LEARNER-2769

This avoids a fatal error in Django 1.9+ in most scenarios, where this
code (before this commit) will no longer result in an implicit __in
query.  This commit should be a no-op functionally for Django 1.8.

More info: https://code.djangoproject.com/ticket/25284

PLAT-1525

Make the support modal responsive

More Sass quality fixes

Merge release back to master

LEARNER-142