Update RX-TX.h

UK will see how to connect the receiver to different pins on the ardiuno (Prob. will need 4 pins)
Also, look for how to get varying pulse width from the receiver needed for analogue input using FHSS...
Till now, we know only 3 types of inputs given...
FYI, the outputs are directly proportional to the width when the pulse is high..

I have to just convert the output into proper format