add back the search bar
extent get_content_cache to return content kinds of a specific type
extend node_cache to add in other kinds that we want
remove unused functions in search autocomplete js
Updates .gitignore to exclude .pyo files.
Adds duration inspection for contentload.
Fixed the videos not loading issue for admin users
Merge pull request #2508 from howdyitshelena/dev

Fixed the videos not loading issue for admin users
Imports additional metadata from files.
Fixed issue with quiz loading (#2509)
Annotates related_content on imported data.
Merge pull request #2511 from howdyitshelena/dev

Fixed issue with quiz loading (#2509)
Updated sidebar to expand to show clicked subtopics, and no sliding.
Remove height specification on slimScroll.
Styling tweaks to sidebar.
Mark intermediate topic nodes as active in sidebar.
Adds related content to content templates.
Refactors 'learn' routing to route by channels.
Loads requirejs unconditionally in topic.html.
Merge branch 'develop' of github.com:learningequality/ka-lite into develop