add play function

[felixroos]

The play function allows adding a pattern to the scheduler, as an alternative to stacking it in the bottom:

stack(
  s("bd"),
  s("~ cp")
)

can now also be written as

s("bd").play()
s("~ cp").play()

this is also how it already works in https://github.com/tidalcycles/strudel/tree/main/packages/web

[felixroos]

play now also returns the pattern itself, which opens up some interesting patterning possibilities:

s("rim(3,8)")
  .pan(0).play()
  .pan(1).rev().play()