Consider supporting P5.js

[ianstormtaylor]

Since P5.js is so widespread, it would be really cool if we could make it so that any valid P5.js script was also valid. Not exactly sure if it's possible or worth it or what it would entail though.

There are certain things like context.random that are much nicer than what P5.js gives you, so I feel like they should still be exposed even though P5.js gives you a few helpers.