Modulestore Support for Content libraries (Part of SOL-1, SOL-2, SOL-3)

Create helper function to remove duplicate code

Fix help modal css selector

This repetitive code is especially pronounced in Stanford's fork, where
we have extended the About page to include several additional fields.

This pays down some technical debt by refactoring into a shared helper.

Revert enable login/registration

Moved has_course_access from CMS to student.auth (common)

Revert "If feature flag is enabled, replace the old login/registration pages with the new combined login/registration page."

This reverts commit f40447b3.

Conflicts:
	lms/urls.py

Revert "Add support for external auth on the combined login/registration page"

This reverts commit 98875339.

Conflicts:
	lms/templates/courseware/mktg_course_about.html
	lms/urls.py

Remove antiquated cleanup script

Remove extra prerequisites style and class

Add compare-branch option to paver run_quality

Fixed plus sign icon for overall grade range add button.

TNL-890

Refrain from setting email opt-in preference when checkbox is missing

FIX - LMS: Calculator Toggle Label Display

Add BI events for tracking email opt-ins

Conflicts:
	lms/djangoapps/mobile_api/course_info/tests.py

Make static URLs absolute in handouts, updates, and about for mobile API

Allowing email optin to work on register.

Cdodge/shopping cart touchups

Sylvia/docs/1162

Login/Registration A/B test cleanup

Fix issue with iframe redirect

Only allow users who turned 13 before this year began to opt in.

Add support for redirect URLs in third party auth for combined login/registration page

Remove old login/registration acceptance tests

Add deprecation warnings to old login and register views

Move third party auth util to student_account

Add exception for microsites

Fixed instructor dashboard tooltip far away issue.

TNL-558