EMC Probe script to home machine using an electronic edgefinder

Setting the home (zero) reference position on my Boss retrofit
using EMC was a bit awkward (of course, I may have been doing
it all wrong): touch the probe to the X and Y side of the material,
move it in the radius of the probe and then zero the axis.

So I've modified probing.tcl to make it as little easier. This
script (probe2.txl) has been uploaded to the files section
if anyone is interested. It's the first (beta) version
and certainly can be improved.

Instead of pointing the probe at an X/Y/Z coordinate, the script
allows probing in one direction: plus or minus in the X or Y
direction. That way you don't have to note your current
position and calculate a desination coordinate.

The probe will move one axis one directin at most one inch at
1IPM or until it contacts the material. Then manually move the
probe over to the other axis with TxEMC and repeat.

Pressing the Home button raises the probe a Z axis clearance,
moves the X/Y axis over the zero reference point (taking
into consideration the probe radius) and zeroes the X & Y axis.

Thanks to the original author of probing.tcl for providing
an excellent blueprint (and apologies for hackimg it!)