add new arguments for update_language_packs, specifically to use a local
zip files as source
fix some wrong use of builtin libraries
look at name of zip file to determine language being processed
reenable SRTs (disabled during dev)
Merge branch '1067' of github.com:aronasorman/ka-lite into lang_code_consistency

Conflicts:
	kalite/i18n/management/commands/update_language_packs.py
Updates to resolve merge issues between branches, extend functionality.
Merge remote-tracking branch 'refs/remotes/upstream/release-0.11.1' into 1067
fix update_srts when 'all' is specified
rewrite extract_new_po to explicitly handle individual as well as all
languages
hackish fix to make the 'all' option run
traverse directory and look for po files instead of looking just one level
combine all po files into one
add option to not download subtitles
extract_new_po returns the location of the po files
adding a doc to record how we pulled together this demo.
get KA strings placed into django.po
Merge branch 'release-0.11.1' of github.com:learningequality/ka-lite into 1067

Conflicts:
	kalite/i18n/management/commands/update_language_packs.py
changing language pack version on every merge with KA data
Merge branch 'bugbash_fixes_1' of github.com:bcipolli/ka-lite into 1067

Conflicts:
	kalite/i18n/management/commands/update_language_packs.py
	kalite/updates/views.py
fixing missed function rename change