original code

this was used to experiment with SPI interface of a digital
potentiometer.
2nd revision using interrupts to measure pulses

used attachInterrupt() function from Arduino to measure the high pulse
time. Then converted this to a throttle servo angle and a steering 1KHz
PWM signal. The 0 interrupt would stop the 2nd interrupt from
completing.
Removed interrupts and used pulseIn()

Changed the program to use the pulseIn() from Arduino library to measure
one pulse and then the next. This means that I would miss 1 or 2 pulses
from either signal, but this only equates to about 40 -60 ms of signal.
Steering and throttle work, no brake at this time.
added braking functionallity

created a brakeSet() and brakeRelease() function to trigger off of the
percent of throttle when it gets to a certain point will test soon.