contains for all shapes.

[ChristerNilsson]

I've been missing an easy way of detecting which shape I'm clicking on in p5.
Especially after some translations, rotations and scalings.
When I found Rune, I was hoping it would solve this problem.
But, there are no mouseclick examples at all.

Polygon seem to be the only class implementing the method contains.
But, it doesn't seem to be the an ancestor class of other classes.

Would be nice if it was possible to ask the stage for a list of shapes containing the point mouseX,mouseY.