Interface Supermodel with original SEGA hardware

[Bart]

We already have migrated to SDL2. In fact, we support both and have not removed XInput/DirectInput (and will probably not).

The Z80 emulation is necessary because the drive board is emulated at a lower level. The emulation does not intercept commands from the PowerPC. Nik wanted to do that (and called it "simulation mode") but never quite got it working well enough for prime time.