CHG: a better micro second (us) spindely function. At average it has 8-10us delay...

CHG:  a better micro second (us) spindely function.  At average it has 8-10us delay, but its linear.  Making error less when you want to wait longer..

SpinDelayCountUs(20) gives a delay of 28us.
SpinDelayCountUs(100) gives a delay of 110us.
SpinDelayCountUs(500) gives a delay of 508us.