Add CMake support for Visual Studio and installation, with an expected "install" for CMAKE_INSTALL_PREFIX, and updated test scripts to consume the CMake installation.

git-svn-id: https://cvs.khronos.org/svn/repos/ogl/trunk/ecosystem/public/sdk/tools/glslang@25791 e7fa87d3-cd2b-0410-9028-fcbf551c1848