AxisStepper: optimize memory usage at expense of 4 instructions in the ISR
AxisStepper: optimize memory usage at expense of 4 instructions in the ISR

ambrop72/aprinter,fixator/aprinter,fixator/aprinter,johnkingsley/aprinter,fixator/aprinter,ambrop72/aprinter,ambrop72/aprinter,johnkingsley/aprinter,ambrop72/aprinter,fixator/aprinter,johnkingsley/aprinter,fixator/aprinter,johnkingsley/aprinter,johnkingsley/aprinter,ambrop72/aprinter,ambrop72/aprinter,johnkingsley/aprinter,ambrop72/aprinter,johnkingsley/aprinter,fixator/aprinter