Make course description pages configurable

[kohlhase]

The Course Description page (e.g. http://panta.kwarc.info/node/16) is currently very basic, it would be very nice, if we could make it more configurable. Here are some ideas of what would be nice,

• not all course pages have schedule information (indeed none of mine has; and unless we want to make it automatically generable, they never will). So it would be good to have a checkbox so that the schedule is not generated in the page. The same holds for all the other areas like description and grading.
• the TAs should be cross-linked to their pages (like the instructor is).