Add ENABLE_DISCUSSION_EMAIL_DIGEST feature, to enable discussion emails digest by default for all users
Add ENABLE_DISCUSSION_EMAIL_DIGEST in api_manager
Add missing setting
Merge pull request #187 from aboudreault/discussion-digest-default-solutions

 Add ENABLE_DISCUSSION_EMAIL_DIGEST
drag-n-drop/discussion: Update hash
ziafazal/api-fix-bug-progress-tab: fix progress

Fixed progress value by using total modules in the course as
denominator.

variable names changes and login for total_actual_completions

efficient way to load leaf modules

 and added required settings to tests
Merge pull request #186 from edx-solutions/ziafazal/api-fix-bug-progress-tab

ziafazal/api-fix-bug-progress-tab: fix progress
mattdrayer/api-course-exists-check: Refactored course lookup logic