Support for Adafruit's DC & Stepper Motor Hat

[zugaldia]

Hey all, I've started adding support for Adafruit's DC & Stepper Motor Hat on Android Things. Code and demo is available here: https://github.com/zugaldia/adafruit-motor-hat.

This is my first Android Things driver, so I'd appreciate any 👀 on common errors and best practices. For now, it's pretty much a line-by-line port of the original Python library (using com.google.android.things.pio.I2cDevice instead).

Feel free to close this ticket, I just wanted to let you know this thing existed :)