(unified branch) Windows to Commodore keyboard driver allows for keys to get stuck

[davervw]

The SHIFT and similar key handling has bugs that a key can be left pressed when it was actually released. Requiring the user to hunt and peck at retyping recent keys to unstick them.

The Windows keyboard driver implemented was a hack implemented quickly. It should be rewritten by porting the equivalent of the USB to Commodore keyboard driver logic (minus USB) as implemented for Teensy 4.1