Merge pull request #1 from nhaehnle/master

Get new chapters
Correct few typos
Enumeration: Start with the probability stuff

Signed-off-by: Nicolai Hähnle <haehnle@or.uni-bonn.de>
Merge remote-tracking branch 'anherm/master'
Merge pull request #2 from nhaehnle/master

Pull probability stuff
Add some missing corollary; suggest a different proof of some lemma
Merge pull request #5 from anherm/master

Some changes