Fix ensure_dir: check that path is actually a directory path
Comment on ensure_dir function
Merge pull request #887 from b3b/develop

Fix ensure_dir: check that path is actually a directory path
Merge pull request #875 from dylanjbarth/bundle_subtitles

Bundle subtitles w/ language packs
Merge branch 'release-0.11' of github.com:learningequality/ka-lite into develop
Fixing up HTML to be compliant, according to http://validator.w3.org/
Merge branch 'release-0.11' of github.com:learningequality/ka-lite into develop
Merge pull request #1070 from bcipolli/khanload_update

Khanload & topic tree update
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