Corrections, new uploads ...

• Big bugfixes in the uploaded 6 and 7ff (document split to reflect reality).
  Also, a technical mishap gave the "6" narrower margins than 50 percent. But I thought: is that an improvement, visually? Here is the 7ff in a version with the same issue. What do you prefer?
• There was one missing item from today's lecture, a page I accidentally flipped over. Will recap tomorrow.
• Looks like we will change time, then. Major revisions expected by Friday.

Nils