Avoid erroring out immediately when an unknown language is hit.  Add some known languages with a "KA_name", to get dubbed video support off the ground.
Simplify / shorten logic, clarify what "lang_codes" really contains. Make it possible to compile all pos, or just one.
Merge branch 'release-0.11' of github.com:learningequality/ka-lite into i18n_command_tweaks
Merge pull request #1125 from bcipolli/i18n_command_tweaks

I18n command tweaks