Improved OpenMesh cmake finder for Xcode 5.1.1 with gtest 1.7




git-svn-id: http://openmesh.org/svnrepo/OpenMesh@1086 fdac6126-5c0c-442c-9429-916003d36597
Improved list of supported compilers

git-svn-id: http://openmesh.org/svnrepo/OpenMesh@1087 fdac6126-5c0c-442c-9429-916003d36597