Make vcamera command syntax more clear.
Restore command vraytrace as alias to vrenderparams.
Replace occurencies of atof() by Draw::Atof() in ViewerTest_ViewerCommands.cxx.
OpenGl_GraphicDriver::Redraw() - do not recompute structures more than required
OpenGl_Workspace::Raytrace() - bind proper FBO before clearing it
Visual3d_View::Redraw() - perform automatic 2nd redraw on device lost