For embedding chat in a course, user testing shows a course tab is
preferable to the slideout thing, and simpler to implement, so this
commit reverts courseware changes.  Instead, embed chat by creating a
new course tab and setting it's HTML to look like this:

  <iframe src="/courses/COURSE_ID_HERE/chat" width="100%" height="640px"
          style="border: 1px solid #c4bfab; border-radius: 5px;"></iframe>

Conflicts:

	lms/templates/courseware/courseware.html