Added code to show a simple example of the on-board A/B/X/Y button press detection and displaying the result on the display, as this feature of the Pico Explorer hardware was not being demonstrated in the initial demo.py example.
* fixed explorer library, added to cmake, and added quick demo
* display status of motors during demo
* increase motor power in demo
Co-authored-by: Jonathan Williamson <jon@pimoroni.com>