fix typo around Theorem 2.12.5, close #350
Remove some stray commas
Reunite a long sentence
Simplify base case of Theorem 7.1.10
Fix a typo: "entires"
Merge pull request #364 from rwbarton/exercise-7.2

Fix a typo: "entires"
Merge pull request #362 from rwbarton/section-7.3

Section 7.3 punctuation fixes
Bring errata up to date and sort by location, #298
Merge branch 'master' of github.com:HoTT/book
minimal fix for #361
align defn of ackermann function with wikipedia, close #360
missing period
Clarify in what sense variables in 1.11 are "unnamed", #347
add 1e868fa to errata
Add fe4641b to errata
Merge pull request #363 from rwbarton/theorem-7.1.10

Simplify base case of Theorem 7.1.10
add 713f48c to errata
Mention why 4.9.2 uses univalence, close #366
add aba76c8 to errata
Merge pull request #369 from mikeshulman/nontrivial4.9.2

Mention why 4.9.2 uses univalence, close #366