Resolves#70, Resolves#67
Still needs some regression testing in general, and a definite
regression is that rotary encoders are no longer (for the immediate time
being) supported.
Moves to a much simpler internal state tracking system, and FAR lighter
matrix scan.
Removes MicroPython support entirely.
This also cleans up some weird potentially-buggy logic paths within the
ModifierKeycode creation and handling. I can now press a free-floating
HYPER in my keymap and see the appropriate codes in `xev` for press and
release events.