Remove transparency from lulu.com covers
Merge branch 'master' of github.com:HoTT/book
Remove alpha channel from Lulu cover images
type of elements -> type of members
(marked) errata for ed2c765
(marked) erratum for 70c069e
oops
Merge branch 'master' into errata
(marked) errata for 6f53189
an exercise relating embeddings to left-cancellable maps
Merge pull request #685 from mikeshulman/errata

Some errata
Merge pull request #686 from mikeshulman/embeddings

an exercise relating embeddings to left-cancellable maps
Merge pull request #677 from andrejbauer/master

Fix covers for lulu.com