Merge branch 'paths_sharing' into 1222

Conflicts:
	kalite/i18n/management/commands/update_language_packs.py
Merge branch 'develop' of github.com:learningequality/ka-lite into 1222

Conflicts:
	kalite/management/commands/zip_kalite.py
Refactor metadata grabbing, incorporate dubbed videos and exercises into language packs.
Merge branch '1164' of github.com:bcipolli/ka-lite into 1222

Conflicts:
	kalite/i18n/management/commands/update_language_packs.py
	kalite/shared/i18n.py
Distributed server side of 1222--move exercises if they exist.
Merge branch 'develop' of github.com:learningequality/ka-lite into 1222
TWO pdbs... record\! :$
Showing # exercises available in language pack, fixing overwrite bug
Add option to skip all updates & inclusion of KA data, put debug output via logging instead of print.
Remove duplicate code for language selection.
Only scrap exercises for languages that we know exercises exist for.
Add missing files, for topic title translations.
Merge branch '1222' of github.com:bcipolli/ka-lite into 1222
Merge branch 'develop' of github.com:learningequality/ka-lite into 1222
Merge pull request #1287 from bcipolli/1222

Include localized khan exercises into language packs