XIAO compatibility

[luni64]

@m-r-m-s and @FerGT50
I improved the XIAO code (development branch) und tested it with the interrupt based encoders (Encoder) the polled encoder with / without buttons (PolledEncoder) and a 74165 based multiplexed setup (8 encoders with buttons, EncPlex74165). My tests show now problems so far. If you find time I'd appreciate some more testing.

[m-r-m-s]

@luni64 sounds good and thank you for the update. It will be a little bit before I can test it out. I still need to get a Xiao dedicated bread board set up with my Din MIDI I/O circuit.

[FerGT50]

Sounds great! Thanks luni!
Will test with XIAO and WeMos D1 SAMD21 M0 Mini next weekend.