Change wood size for 4th mold. Improved documentation.

- cw.py: switch from 1/2"x2" wood to 1"x3"
- README: explain what we need to protect against
- README: added more process details
- README: merged g2gp pass into "doit"
- doit: script for final machine-specific alignment and translation

doit

@@ -0,0 +1,46 @@
+#!/bin/sh -e
+#
+# doit - Generate RML-1 job from gnuplot toolpath
+#
+
+DIR=/home/moko/svn.openmoko.org/developers/werner/cncmap
+G2GP=$DIR/g2gp/g2gp
+RECT=$DIR/rect/rect
+ALIGN=$DIR/align/align
+ZMAP=$DIR/zmap/zmap
+GP2RML=$DIR/gp2rml/gp2rml
+
+# 1st mold. 1/2"x2" pine. Did't have space for the battery cover's tongue.
+rdata="10.50 8.40 -33.40  138.30 8.00 -34.00  10.50 50.10 -33.40"
+rdata="14.50 5.90 -33.40  138.30 5.50 -34.00  14.50 50.10 -33.40"
+Z=-34
+
+# 2nd mold. 1/2"x2" pine. Six air outlets.
+# correction: x+2.5, y-3, z-0.2
+rdata="11.8 10 -33.9  137 10 -33.6  11.8 51.5 -33.6"
+rdata="14.3 7 -33.9  137 7 -33.6  14.3 51.5 -33.6"
+Z=-33.8
+
+# 3nd mold. 1/2"x2" pine. Seven air outlets.
+# correction x+2.5, y-2, z-0.2; z is very uneven
+rdata="12.1 8.1 -33.2  139.4 8.1 -33.3  12.1 50.2 -33.9"
+rdata="15.6 6.1 -33.2  139.4 6.1 -33.3  15.6 50.2 -33.9"
+Z=-33.5
+
+# 4th mold. 1"x3" pine. (Shop changed wood sizes. 1/2"x2" is now too small.)
+# correction: x+3.5, y-1.5, z-0.0
+# rotation: compensate for piece misalignment, y0 is 1 mm larger than y1
+rdata="11.8 8.5 -23.4  11.8 73.3 -23.5  137.3 8.5 -23.2"
+rdata="15.3 7.0 -23.4  15.8 73.3 -23.5  137.3 6.0 -23.2"
+Z=-23.5
+
+# cast*.g is HeeksCAD's NC output.
+
+rect=`$RECT $rdata | awk '{$3 = ""; print}'`
+
+$G2GP cast4.g |
+  awk '{ if ($3 != "") $3 += '$Z'; print $0; }' |
+  $ALIGN 0 1 $rect |
+	# angle, reference (lower left), rect
+  $GP2RML 20 5 5
+	# clearance, xy speed, z speed