update notebook

[jovo]

• in input 1, why is it "A \sim \element \sim \Real^{n \times d}"? i would think it would be "X \in \Real^{n \times d}"
• does k-means not output the means?
• is "<" equivalent to "comment" in some programming language? which? i expected a "%" or "#". oh, because latex uses a triangle? maybe use that same symbol then?
• step 3 missing paren
• step 5 missing curly
• step 5Bc: "endfor" is on wrong line, and there is a 3 in front of it.
• endfunction belongs on its own line