Sylvia/docs/sfd discussions

@mhoeber @lamagnifica @catong This is finally ready for review. I accidentally added some extra images, so please ignore the ones that don't apply (I'll take them out before I merge this). I tried to create a built version but RTD inexplicably created the course staff release notes page (grr); will try again tomorrow.

Update: RTD is working! See http://draft-sfd-discussions.readthedocs.org/en/latest/.
right, so it looks like the count (1 discussion) on the left does not match the actual number of top-level posts shown on the right. I think this is a problem with your image -- could it be a compilation from multiple screenshots?
I tested this in the software, and find that the biggest problem is actually that the terminology on this page hasn't kept up with our changes in labeling. Under a single user login, I created one discussion (post), added one response, and then added one comment. I repeated for a question (post). The result is, on the left, "2 discussions started 4 comments" (counts are correct) and on the right, two boxes with the titles and first lines of the two posts (correct). The only issue in the software is that both responses and comments are lumped together and labeled "comments" which might be confusing, but reflects how the mongo database stores them.
I'm really not sure that this particular feature needs a spotlight on it...