Jon Freeman / Mbed 2 deprecated cnc_machine_driver_3

Code to drive a CNC machine via a PC LPT port lookalike 25 pin 'D', experiment in 'PC/Mach3' replacement. Designed to compile and run on mbed LPC1768, Freescale KL25Z and Freescale KL46Z. Proved on LPC1768 and KL25Z, problem with serial port on KL46Z. Reads subset of 'G Codes' through usb/serial port and drives 3 stepper/servo drives for X, Y and Z, also similar Step/Dir outputs for spindle motor control. Emulates PC LPT, outputs 'charge pump', proved driving Seig KX3 CNC mill

Dependencies:   MODSERIAL mbed