Updated required CMake version
Updated required CMake version

We update CMake version so as to use `CMAKE_CXX_COMPILER_VERSION` variable that has offcially been released in CMake 2.8.10
This is related to issue #482
simbody/simbody,Gjacquenot/simbody,Gjacquenot/simbody,Gjacquenot/simbody,simbody/simbody