Arduino S Function for MPC4725 I2C DAC

This is an S Function driver for the MPC4725 I2C Digital to Analog 12 bit converter.

I needed to make this work for a project and finally did by following the S Function Builder tutorial that was posted Here: http://www.mathworks.com/matlabcentral/answers/74044-s-function-builder-help

I've also made an S Function with this same process for the ADS1115 I2C 16 bit ADC using the adafruit ADS1015 library but I'll post that later.