Add schedule for next weeks.
Link to lecture notes.
Add material from first exercise session.

This is just the file as it was at the end of the exercise session, so
that students can start experimenting with it. I plan to edit it to add
more comments and more details about the homework organization.
Link to material from 1st exercise session.
Fix homework: replace 'Negation' by 'Subtraction'.
Explain homework and add first assignment.
Fix first homework deadline.
Merge pull request #2 from klauso/master

Update