Python code for driving the Adafruit LCD Backpack Code much influenced and copied from the Adafruit libraries for Arduino: See https://github.com/adafruit/LiquidCrystal and https://github.com/adafruit/Adafruit-Raspberry-Pi-Python-Code/tree/master/Adafruit_CharLCD
This is using an MCP23008 IO expander to drive the pins on an HD44780 LCD driver