Use pr1/2 rather than projT1/2
Use pr1/2 rather than proj1/2_sig
Fix etc/install_coq.sh on OSX
Forgot to ucomment popd
Merge pull request #439 from andrejbauer/master

Fix /etc/install_coq.sh for OSX, merging because this is a technicality.
Merge pull request #437 from mikeshulman/pr

Use pr1/2 rather than projT1/2