added django admin pages for Coupon Table

added the suggested changes by cdonge
registration code checkout flow

Redirecting to dashboard after free user enrollment.
added course price set/view/edit functionality

added CoursmodeArchive model to save the old prices history

analytics -> instructor_analytics

analytics -> instructor_analytics
refund message for purchased courses

Add little more logic for paid courses
add more detail to new CourseModesArchive table
e-commerce UI suggested changes
Retrieving active coupon codes from model
Merge pull request #4254 from marcore/fix-branding-course-listing-opaque

Fix filter with new opaque key, allowing user to set COURSE_LISTING as o...
Annotations Tools: Fixing major Firefox/Tinymce bug in annotations

 - fixed issue in Firefox where the init gets called multiple times

 - fixed spacing issues and added more comments

 - fixed indentation, added missing parens in comment, and fixed typo
Merge pull request #4655 from edx/diana/allow-only-verified

Allow verified to be offered without audit
Update youtube api.
Merge pull request #4693 from edx/anton/fix-video-tests

Fix failing video tests due to wrong IFRAME_API_RESPONSE
Correct UnboundLocalError exception in student_migration_35
Text Annotation Tool: Safari Colored Highlights Bug Fix

 - fixed spacing
Merge pull request #4590 from edx/cdodge/fix-reg-codes

eCommerce enhancements (pt. 2)
Merge pull request #4675 from lduarte1991/lduarte-harvardx-pr14

Annotations Tools: Fixing major Firefox/Tinymce bug in annotations
Merge pull request #4518 from lduarte1991/lduarte-harvardx-pr13

Text Annotation Tool: Safari Colored Highlights Bug Fix
Replace `check_for_get_code` with `assert_request_status_code`

More flexible, uses the word "assert", method instead of function
BLD 1020: Easy access to Group Configurations page from Content Experiment component.
Added enrollment breakdown by certificate track