Add ability to control border width by "in" or "mm" instead of only "px"

Add the ability to control exact width of strokes and borders. I would like to be able to control these down to the Nth decimal place (at least to 0.001 in)

Use case: I am making files for use with the Epilog laser system, which only reads a stroke with RGBa value (255,0,0,100%) and width of 0.001in as a "cut" line, and all others as etch.

This level of control is possible in Inkscape.