Removed unused discussion-app.css, corrected utils.py to streamline icluding discussion js files
Reworked discussion assets management to work on production like environment (pipelines+nginx proxy)
Fixed broken backbone history navigation in course mode. Moved runtime-specific settings modifications to runtime callbacks.
mattdrayer/api-2632-fix: Fixed bugs related to proforma grade calculation/retrieval
Added discussion xblocks to course categories map
Fixed changing thread type
Copied discussion tests from upstream
Merge pull request #323 from open-craft/eugeny/discussion-backport

Production deployment fixes
Merge pull request #324 from edx-solutions/mattdrayer/api-2632-fix

mattdrayer/api-2632-fix: Fixed bugs related to proforma grade calculatio...
Fixed production deployment issue caused by staticfiles url replacements (see replace_static_urls/__init__.py -> replace_static_urls)
Merge pull request #329 from open-craft/eugeny/discussion-backport

Production deployment fixes -> staticfiles url rewriting
Fixed missing `user` context variable in dicussion course + switched to using more efficient `cached_has_permissions`
Merge pull request #330 from open-craft/eugeny/discussion-backport

Discussion course production deployment issues fix
Missing fix for static URL rewriting in discussion course
Merge pull request #331 from open-craft/eugeny/discussion-backport

Missing fix for static URL rewriting in discussion course
tie into the xblock publish API point for progress and grading events