m65c02.h WDC65C02 emulator code

[c1570]

Not 100% finished but runs tests fine. Are you interested in this? Might come in handy for Atari Lynx or Apple IIe/IIc/BBC Master emulation. https://en.wikipedia.org/wiki/WDC_65C02#Uses

[floooh]

Are you interested in this?

Maybe when a system which needs this CPU is added at some later point, but until then I think it's better when it's parked here in a PR :)

PS: ignore the failing CI, that's unrelated. I have updated the chips-test repo which is used in the CI to a different "meta-build-system" (http://github.com/floooh/fibs), but also need to update the CI scripts here in the chips repo.

[c1570]

Sure! I added a link to this PR in the m65c02.h header to make things a bit more clear.

FWIW this is used in tests for the Sorbus 65C02 Computer: SvOlli/sorbus#4