Build for more platforms

[jmaroeder]

At the very least:

• MacOS
• Windows
• Linux ARM

[jmaroeder]

Windows has issues building simavr. These have been reported in the simavr repo, but attempting to incorporate these reveal how brittle the reliance is upon simavr.

It may be time to rewrite the AVR simulator, as this is also impacting #2.

[phcoder]

#13 adds a whole bunch of platforms