Improve usability of add tag widget
Rename user template for consistency
Improve dropbox instruction for add tag widget
More consistent layout for add tag contents
Slim border for add tag widget
Fix mixed content error when using https

Recent browsers disallow mixed content for pages accessed securely.
The solution here is to switch our YouTube embed urls to use protocol
relative links by excluding the scheme, so it will match the protocol
the server is using.
Remove header on citation widgets
Filter parents from add tag drop events
Add discuss link to argument widget
Add CommentEditor and DiscussionEditor modules
Integrate DiscussionEditor with Argument widget
Make asset files non-executable
Add on_create optional callback for editors
Add Comment widget module
Add Discussion widget module
Integrate Discussion and Argument widgets
Add Moment.js library
Display a short comment date after author
Upgrade jQuery.autosize to latest version
Fix autosized height of comment textareas

The autosize plugin can't calculate the size of hidden elements, so we
must force a recalculation after the element is revealed.  It provides
an event binding for this purpose (`autosize.resizeIncludeStyle`),
which we now trigger the first few times the size is adjusted.