NEO GEO for MiSTer

This is an FPGA implementation of the NEO GEO/MVS system by Furrtek

The only modification in this fork is a tweaked main clock from 24MHz (MVS) to 24.167829MHz (AES) (taken from here).

This allows having a refresh rate of 59.6Hz which is closer to the NTSC standard and should be accepted by some devices which do not like "exotic" refresh rates such as the BKM-68x or some plasma TVs.