fix issue #1136: Show installed languages in the update videos page.
reorganize available language packs text in /update/videos
fix issue #1137: Add english to list of languages if we don't have a
language pack for it
Don't show "set as default" link if language is already set as default
Merge branch 'release-0.11.1' of github.com:learningequality/ka-lite into lang_code_consistency
fixing bug in dictionary storage and cross-data validation code