Fix the numbering of (Bool <~> Bool) <~> Bool

Reported By: Edward Z. Yang <ezyang@mit.edu>
udpate INSTALL.txt

with help for solving the Mac OS X problem involving the -fno-defer-pop
problem
Merge pull request #344 from JasonGross/fix-bool-equiv-bool-book

Fix the numbering of (Bool <~> Bool) <~> Bool
Merge pull request #345 from DanGrayson/pull-document-fix-mac-os-x-clang-option-problem

udpate INSTALL.txt