Add support for Adafruit Circuit Playground Bluefruit

[oenone]

Add support for Adafruit Circuit Playground Bluefruit.

With STACKSIZE > 0 it gives stack overflows for the benchmarks "Hofstadter Q sequence" and "Two-dimensional recursive function Q2".

Why does function playnote() check the pin in that range? That should be broken on Adafruit CLUE, too, so I removed it.

[technoblogy]

Thanks for this, and sorry for the delay in responding! I'll add it to the next release.

[technoblogy]

I've added your suggestions manually to the latest version 4.4 - thanks for suggesting them.

[technoblogy]

@oenone You might be interested in this:

Have fun with uLisp on the Circuit Playground Bluefruit