Merge branch 'develop' of github.com:learningequality/ka-lite into translation_scrub
Refactor video utils into more generic utils.internet.download
Add the progress bar; get callbacks about % downloaded along the way.
small styling tweak to vertically space things out
Merge branch 'develop' of github.com:learningequality/ka-lite into 1141
Merge pull request #1299 from bcipolli/1141

Add progress bar for language pack updates