fix 6.10.12, close #574 and #577
fix section 8.1 to match new 6.10.12
an exercise for the other definition of Z
unmarked errata for de14e6b
one more erratum
yet another erratum
Updated Reading_HoTT_in_Coq for Coq 8.4pl3
improve notation
Merge branch 'master' into integers

Conflicts:
	errata.tex
clarify ex 9.4, close #590
Merge pull request #592 from mikeshulman/pre2categories

clarify ex 9.4, close #590
quotation style, change /.''/ and /,''/ to /''./ and /'',/ only
remove extra spaces
Merge pull request #593 from Shark64/quotation-style2

Quotation style second try
fix typos, close #595
unmarked errata for 4818f12
Merge pull request #596 from mikeshulman/lemma6.12.4

fix typos, close #595
Mark Errata (auto)
Merge pull request #583 from mikeshulman/integers

fix 6.10.12, close #574 and #577
Mark Errata (auto)