button: Support half-stepping encoders
Adds support for half-stepping encoders (encoders that only emit two
steps per detent, instead of four). Incorporates the feedback from
@susisstrolch's PR: https://github.com/KevinOConnor/klipper/pull/4202
, which was itself built upon a previous PR from @nickbrennan01:
https://github.com/KevinOConnor/klipper/pull/730
Uses the table from the Rotary Arduino library linked in buttons.py:
6b784cca67/Rotary.cpp (L21-L40)
Signed-off-by: Rufo Sanchez <rufo@rufosanchez.com>
b336a21fe7