delta_calibrate: Add initial support for a DELTA_CALIBRATE command

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>

config/example-delta.cfg

@@ -107,3 +107,28 @@ delta_radius: 174.75
 #   axis towers. This parameter may also be calculated as:
 #    delta_radius = smooth_rod_offset - effector_offset - carriage_offset
 #   This parameter must be provided.
+
+# The delta_calibrate section enables a DELTA_CALIBRATE extended
+# g-code command that can calibrate the tower endstop positions and
+# angles.
+[delta_calibrate]
+radius: 50
+#   Radius (in mm) of the area that may be probed. This is typically
+#   the size of the printer bed. This parameter must be provided.
+#speed: 50
+#   The speed (in mm/s) of non-probing moves during the
+#   calibration. The default is 50.
+#horizontal_move_z: 5
+#   The height (in mm) that the head should be commanded to move to
+#   just prior to starting a probe operation. The default is 5.
+#probe_z_offset: 0
+#   The Z height (in mm) of the head when the probe triggers. The
+#   default is 0.
+#manual_probe:
+#   If true, then DELTA_CALIBRATE will perform manual probing. If
+#   false, then a PROBE command will be run at each probe
+#   point. Manual probing is accomplished by manually jogging the Z
+#   position of the print head at each probe point and then issuing a
+#   NEXT extended g-code command to record the position at that
+#   point. The default is false if a [probe] config section is present
+#   and true otherwise.