Some more probe cleanup

[AnHardt]

-    if (probe_action & ProbeStow) {
+    if (stow) {
       stow_z_probe();
     }
+    else {
+      do_probe_raise(max(current_position[Z_AXIS],Z_RAISE_BETWEEN_PROBINGS));
+    }

is the key idea in probe_pt(). The rest is more or less the concequences.

And a simple servo tweak to prevent the probe from moving before the servo is at its target angle.

Not very well tested.

Best viewd with https://github.com/AnHardt/Marlin/pull/48/files?diff=unified?w=1

[thinkyhead]

Looks like a reasonable simplification. The probe_pt function was a little "overdesigned."

I found a cool trick… It turns out I can create a PR from any fork using the usual form…

https://github.com/MarlinFirmware/Marlin/compare/RCBugFix...AnHardt:more-probe-simplifications?expand=1