First pass to add footer; addresses #1522 and #1523
Tiny tweaks to logo styling
bundle youtube_dl and use it as a library
Add back callback_url parameter, to complete distributed server registration via a direct callback url.
remove inline styles and disabled classes
Merge branch '1522' of github.com:bcipolli/ka-lite into 1522
Merge pull request #1583 from bcipolli/1522

Changing footer and language drop-down styling
Fix for #1457 - don't show "current" progress bar when using youtube-dl in video download
Fix for display of server default language
Merge branch 'release-0.11' of github.com:learningequality/ka-lite into release-0.11
Fix for #157, #361 - urlencode "next" get parameter, so querystring args on the "next" url are preserved.
Merge pull request #1586 from bcipolli/1457

Fix for #1457 - don't show "current" progress bar when using youtube-dl in video download
Fixing wording issues for #1594
Make sure that current and default languages are *always* within the set of available languages.
Fixing up calls to select_best_available_language (flipped parameter order) for #1601
Remove "test" from basic_addition exercise, unlink subtitles info from topic page.
Revising stats schema, implementing limits on ndays
First pass to show download log summary for videos and language packs.
Filtering data based on # days before present
Better sorting, tighter display