sidebar update

I've re-arranged the sidebar area a bit.

1. All of the visiting scholars and relevant deadlines for posting questions are posted first.
2. Next you see the posted book conversations and relevant deadlines.
3. Third are the conversations still be to recorded and their recording dates.
4. Fourth you'll see links to each of the blog groups.

All of the rest of the material in the sidebar area is the same as before. I'd done this rearrangement to make it a bit clearer about the various assignments and relevant deadlines.