C4&C7 digital input to support more modes

[ElDominio]

Change hardware setup to make C4 a full digital input, able to receive 12v/5v or ground when pullup is enabled.

[mck1117]

Hardware should already be a full digital input, no? Permanently enabled pullup, tolerant of +-24V or so.

[ElDominio]

Some people wire, for example, the positive switch of a nitrous solenoid as a "nitrous engaged" input, so being able to disable the internal pullup is important for usecases like this

[rusefillc]

rev A status: C4 response to GND (at the moment we always have pull-up)

[ElDominio]

I'd say C7 is fine being as it is (although the pullup should be selectable, some Chryslers have sensors with built-in pullups), C4 does need more modes

[andreika-git]

Done. Added selectable 5v-pullups or pulldowns for C4 and C7.

[andreika-git]

Warning! LEDs will be inversed if pulldown mode is selected for CAM or 2STEP.