Add Supermodel3 As A Runner

I am a bit of a fan of Sega arcade games. Knowing the status of MAME with games on the Model2 board and beyond, those who do wish to play games like SCUD Race and Daytona 2 has to compile their own copies of Supermodel. It would be an interesting idea to include it as a runner to not only provide an easy way for a working copy of Supermodel, but to provide further organization.