performance restored
inline intoDelOne; performance OK
inline intoInsZero; performance OK
inline intoMatOne; performance OK
removed unused code intoMatOne
removed special case for I/o/i; slight improvement
remove special case for D/1/i; performance OK
reorder cases
correct code to use `predUnless j`; performance is OK
stateRight is now stateHat; added extra Mat1 predecessor (with no performance change)