Marlin Inch Mode still shows MM in DRO

[cheton]

See cncjs/cncjs#498 for details.

Marlin always reports positions in mm, regardless of whether it is in inch (G20) or mm (G21) mode.

We need to provide a fix for the edge branch:
https://github.com/cncjs/cncjs-controller/blob/edge/src/Controller.js#L403-L418
https://github.com/cncjs/cncjs-controller/blob/edge/src/Controller.js#L478-L493