Update Part 1 to also work with Mayfly

[aufdenkampe]

Presently for Uno and clones.
Make to work with either Uno or Mayfly, by giving a side note for how pins on Uno map to pins on Mayfly.

[fisherba]

I would be happy to have the new edits proofed and tested, but part 1 has been edited for Mayfly.