message: Cite exact cmake version
diff: @@ -28,7 +28,7 @@ Build requirements
  tested with clang++-7.0.2 on Mac OS X 10.10,
  tested with Microsoft Visual Studio 2015 VC14 for x64)
  -- [CMake][1] version 2.8 or newer
  +- [CMake][1] version 2.8.9 or newer
  - [Boost][2]
  - OpenGL
  - [GLEW][3]
  