Frugal RAM/ROM 512K for RC2014

This is a low cost RAM/ROM 512K for RC2014. It is compatible with Wayne Warthen's ROMWBW and also includes a CF interface as well as an I2C interface. Discussion about this board can be found here: https://groups.google.com/g/rc2014-z80/c/TvsdMFqeT9c FRR512K was first prototyped with ProtoRC3. This links to the Prototype FRR512K.