Added Marlin-compatible script for use with a Zero Cube

[Domush]

This script enables the automation of zeroing out new bits to a workpiece using a conductive Zeroing Cube (link to matching 3d printable cube included), while also automatically measuring and accounting for bit radius.

Intended for Marlin 2.xx users, but will likely work with other firmware

Fully documented

[Domush]

This script is ready to go for those who run Marlin and are tired of manually finding (guessing) where the center of the bit is and aligning it with the lower left of your work piece.

Makes bit changes a breeze.