Proper Circuitpython support

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should be pretty straightforward - mostly just making sure pinouts are mapped correctly:

https://learn.adafruit.com/how-to-add-a-new-board-to-circuitpython/overview

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work in progress at https://github.com/tigard-tools/circuitpython/releases/tag/first-try

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once done, then do https://learn.adafruit.com/how-to-add-a-new-board-to-the-circuitpython-org-website

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updated pin names in tigard-tools/circuitpython@c265490
will final test on prototypes before committing.