🥳 New feature: entity class composition with reusable component sets

I added the new extends keyword to the EntityBuilder DSL because a lot of entities start out with the same handful of components, and repeating all of this boilerplate in each new entity definition can end up obscuring all the interesting stuff that makes each one of those entities different. Now you can mix and match component sets and reuse them by extending the components of another class, or even merge several other entities together.

You can use extends to merge the set of components and default attributes from one or more existing entities to create new ones through composition rather than inheritance.

Example

Shape = entity do
	Position()
	Scale()
	Rotation()
end

Container = entity do
	Position({ x: 0, y: 0})
	Scale({ width: 1024, height: 1024 })
	Centered()
end

Label = entity do
	extends Shape
	Text()
	Font()
end

Title = entity do
	extends Label, Container
	Text({ color: "#cca533".rgb.lighten(0.25) })
	Font({ size: 48 })
	Visible()
end