Fix/foldit leaderboard

set django-wiki to its most recent version

Simple port of Class2Go's chat feature

POST requests were claiming request.method == 'PUT'

Fix/vik/studio oe

Ned/studentmodulehistory cleaner command

So, changed handlers to look for either value.

Bug report: remove <?xml version..> tag

Fixes code_jail imports and draganddrop yaml

I18N work seems to have lost a very prominent space in the landing page

add a new django-admin command to dump out a course structure document. ...

https://edx-wiki.atlassian.net/browse/STUD-428

Rebase on today's master and update to unit test to include settings
where needed.

Only render the chat widget if both the site has enabled it in the
`MITX_FEATURES` and if the course has enabled it. In addition, fail
gracefully with a log warning if the `JABBER_DOMAIN` is not set, and
do not try to render the widget. However, do go ahead and render the
rest of the courseware.

To protect against chat blowing things up, we include a way to
enable and disable it on an entire site-wide basis.

Ensure that the chat connection settings are generated properly for
the template context.

jQuery already available across the whole site at the top level, so
no need to include it again specifically for the chat widget.

Embed a chat widget (much like the calculator widget) into the
courseware. To use, you must point it at an ejabberd box,
configured as `JABBER_DOMAIN` in the settings.

Use CodeJail with FSIZE support, and default to 50k

Fix due/start date setting in edit_subsection

including allowing javascript to serialize date/time natively.

Adds in changes for stat2.3x question type

Add XBlock bulk saves to LMS/CMS

Update existing tests and provide new ones to test new paradigm.

Refactor new set_many and update XBlock version number.