The LMS comment client previously would try to parse the response
as JSON, choke, and return a 500 to the client. Now, the LMS client
displays a message indicating that the forums are down for
maintenance.

This reverts commit 2df3fe93.

Conflicts:
	common/static/coffee/src/discussion/utils.coffee

This reverts commit acfd0d9f, reversing
changes made to e4194c99.

add fixes for 500 bugs (lighthouse 287 and 293) by requiring login for accessing licenses and inline discussions.  Add unit tests for licenses, and rearrange tests based off of (the former) PageLoad.  Also cleanups for pylint and pep8.

This reverts commit e4819a1b, reversing
changes made to b6ec41ca.

Now that we're ready to test again, need to revert the revert to put the filtering UI back in.

This reverts commit 66889b87, reversing
changes made to 0dd9c24e.

This was merged too early--it's still missing the filtering and display-your-cohort changes.
Will need to revert this revert later.

This reverts commit 965e3b4c, reversing
changes made to 1a7d2a06.

I accidentally merged this before it was ready.  This was silly, so now I'm undoing it.  We'll need to revert the revert later.