subtract2dFunction in std::sketch

Use a 2-dimensional sketch to cut a hole in another 2-dimensional sketch.

Name	Type	Description	Required
`sketch`	`Sketch`	Which sketch should this path be added to?	Yes
`tool`	[`Sketch`; 1+]	The shape(s) which should be cut out of the sketch.	Yes

Sketch - A sketch is a collection of paths.