+more keystroke commands
+
+speed changes immediate
+
+race between cdu off (due to watchdog or short) and points
+
+
layout polarity diagram colourful segment encoding:
- have to fix it so that points' fixed bits are always drawn
- implement segmap so that we can do midx
- decide what to do about crossings (difficult to show both tracks)
+ make moveable feature selection in subseg2display bitwise rather than
+ setwise
-1. Write lots and lots and lots of PIC programs
+safety system no crashes at crossovers please