What I think is better style
Inverses for Cauchy reals
Merge branch 'master' of github.com:HoTT/book
Some intermedate version of reals, don't look
Merge branch 'master' of github.com:HoTT/book
too many negations
Rephrased wording around unique choice.

I reordered the paragraphs so that type theory is not cut in half by set theory.
I tried to simplify the explanation of what happens in set theory.
It is irrelevant that in *formal* set theory we never construct anything, because in informal set theory we do, and mathematicians know this. We should compare informal to informal.