avoid retransmitting too often (S9.2 C l114-)


layout polarity diagram colourful segment encoding:
 make moveable feature selection in subseg2display bitwise rather than
  setwise



hardware problems

@2011-01-10 22:42:18 GMT info save-dump +dump.2011-01-10T22-42-18+0000
	shinkansen 2nd bogie only derailed at B9, running anticlockwise
	first bogie went correctly to C9; 2nd bogie appears to
	have gone towards B10; B9 was set P9/J0P1 as expected

	examination of realtime log shows most recent firings of
	points for B9 were (a) some time previously (b) to P9/J0P1
	as expected.  So track fault or something, probably.