Merge branch 'video-update-update' of github.com:bcipolli/ka-lite into allow-mem-cache
Move all cache invalidation into create/delete signals on VideoFile objects
Migrating back to bulk_create, and using property update of percent_complete=100 to trigger cache invalidation
Merge branch 'release-0.11' of github.com:learningequality/ka-lite into cache-invalidation-via-signals

Conflicts:
	kalite/shared/caching.py
simple code refactor, with no particular purpose
Merge branch 'release-0.11' of github.com:learningequality/ka-lite into cache-invalidation-via-signals
Merge pull request #913 from bcipolli/cache-invalidation-via-signals

Cache invalidation via signals