light-netsender: RGB light control.

[Ella Di Stasio]

This enhancement is for a feature that allows the user to define the colour of a four pronged LED through VidGrind (using multiple GPIO pins). The user should be able to choose an intensity of red, green, and blue from 0-255, which will likely be done by using pulse width modulation (PWM) through GPIO.

The following document refers to previous work relating to this issue:
https://docs.google.com/document/d/127J-JUI_6kwp8kCbn_ZzBJG6cVDy-ePq1zAKZywsW8Q/edit?usp=sharing