Front-end compatibility

Use front-end and runtime system with the same version number for better compatibility and GUI related bug fixes.

Some 2.5x bug fixes and new features needed modifications inside the runtime system (fglrun) and front-ends (gdc, gwc). Therefore, if you upgrade the runtime system to the latest 2.5x version, we strongly recommend that you upgrade your workstations with the latest front-end version 2.5x as well.