solve #1316: dirty fix to use polib.save_as_mofile instead of django compilemessages
download KA Lite translations by default!
just yield the po files we found if we're not processing KA po files
make utf-8 the default encoding for everything
Merge branch 'develop' of github.com:learningequality/ka-lite into 1316

Conflicts:
	kalite/i18n/management/commands/update_language_packs.py
Merge pull request #1333 from aronasorman/1316

1316 plus a few more fixes on update_language_packs