Primarily used to independently home both sides of a dual-motor gantry with a pair of limit switches (second shared with Z-axis limit pin). An axis motor is efficiently mirrored to a dedicated set of step and direction pins (D12/D13 or A3/A4) with no detectable loss of performance. New dual motor support feature for gantry CNC machines. NOTE: Default build remains the same! Dual motor support can only be enabled in config.h. Dual motor support for self-squaring gantry homing. This release fixes minor bugs and includes a new optional dual motor support for self-squaring gantry homing.