OpenGl_Texture::Init2DMultisample() - new method to initialize multisampled texture.
Graphic3d_RenderingParams::NbMsaaSamples - add option defining MSAA samples number.
RayTracing will keep using FBO without MSAA, however it is possible to combine
MSAA for rasterization and FSAA for RayTracing.
OpenGl_FrameBuffer constructor has been changed to do not take arguments.
OpenGl_FrameBuffer::Init() method has been extended with mandatory parameters
defining Color and Depth attachment formats
and optional parameter defining number of MSAA parameters.
Draw Harness, add option -msaa to vrenderparams.
