Added bash script for installing GCC 4.7.1 using homebrew (Mac only)
Added bash script for installing GCC 4.7.1 using homebrew (Mac only)

johnmarinelli/nmatrix,wlevine/nmatrix,thisMagpie/nmatrix,johnmarinelli/nmatrix,agisga/nmatrix,janusnic/nmatrix,wlevine/nmatrix,janusnic/nmatrix,agisga/nmatrix,thisMagpie/nmatrix,wlevine/nmatrix,wlevine/nmatrix,janusnic/nmatrix,agisga/nmatrix,thisMagpie/nmatrix,johnmarinelli/nmatrix,janusnic/nmatrix,agisga/nmatrix,johnmarinelli/nmatrix,thisMagpie/nmatrix