Merge branch 'update_language_tweaks' of github.com:bcipolli/ka-lite into release-0.11.1
 branch 'release-0.11.1' of github.com:learningequality/ka-lite into release-0.11.1
Remove "parent" and "parents" from all code.
Remove exercises that are not "live" (there were 10), and tweak logging.
Topic tree updates
missed the module qualifier on NODE_CACHE
Solved problem for wrong node cache. Now, truly fixed!
fixing bugs and code readability
Merge pull request #1151 from bcipolli/topic_tweaks

left-over code tweaks from cross-merge