Typeset explicitly defined functions, sets, constants, etc. in roman as per ISO 80000-2:2009. This also coincides with the conventions used in the lecture notes.
Forgot to pull before branching.
Added examples by Raisa Galimova.
First half of the lecture.
First draft of the lecture
Merge pull request #16 from eggrobin/lecture-2013-03-21

Lecture 2013 03 21