Update examples to work on Blue/PocketBeagle

[jadonk]

Should we have something like the below?
var mypin = b.firstValidPin(["P1_2", "P8_12", "GP0_3"]);

Definitely need Python and JavaScript to generate clean error messages when unused pins are specified.

Can we add a welcome page to Cloud9 IDE?

[jadonk]

Recommendation from others (not me) is to make different directories.

[fivdi]

How can this be extended in the future? For example, if a new board is released in the future with a header called P1 just like the the PocketBeagle? If pin P1_2 on the new board is AIN0 would this not conflict with P1_2 on the PocketBeagle which is GPIO87 or AIN6?