add scripts to Xcode project

no need to build them, but nice to have
a reference when you need it
fix cmake not found in /usr/local/bin

explicitly add /usr/local/bin to PATH when
executing cmake for libgit2.
add quotes to variable assignment

+ move it to top of file
Merge pull request #150 from diederich/features/findBrewCMake

Search for cmake in /usr/local/bin