Prevent extra pin events with luacontrollers, microcontrollers, and FPGAs

[TurkeyMcMac]

Fixes #569.

These devices now only run their code when action_change actually changes the state of a port.

I have tested this with circuits from Mesecons Lab.

@Makefile-dot-in, does this fix your issue?

[sfan5]

Tested a bunch, looks good.

[Desour]

👍 Code looks good (you could document the new return value though). Also did some quick test, works fine.

[Makefile-dot-in]

it seems to fix the issue for me too, although I would've preferred a solution that would prevent action_change from being fired in the first place if there is no change. That would probably require larger modifications to track mesecon states though, so I understand why this solution was used. (and overall the effect is rather minor in other effectors)