Cleanup pins files, fixup analogtodigitalpin, etc.

Marlin/Marlin.h

Marlin/pins.h

Marlin/pins_5DPRINT.h

Marlin/pins_99.h

Marlin/pins_A4JP.h

Marlin/pins_BRAINWAVE.h

Marlin/pins_BRAINWAVE_PRO.h

Marlin/pins_CHEAPTRONIC.h

Marlin/pins_ELEFU_3.h

Marlin/pins_GEN3_MONOLITHIC.h

Marlin/pins_GEN3_PLUS.h

Marlin/pins_GEN6.h

Marlin/pins_GEN7_12.h

Marlin/pins_GEN7_14.h

Marlin/pins_GEN7_CUSTOM.h

Marlin/pins_LEAPFROG.h

Marlin/pins_MEGACONTROLLER.h

Marlin/pins_MEGATRONICS.h

Marlin/pins_MEGATRONICS_2.h

Marlin/pins_MEGATRONICS_3.h