hello !

this would allow easily adding animations when using the Children component (and so children![] macro)
use case:

let bundle = (..., Children::spawn_with(|mut p| {
	p.animation() // impl on RelatedSpawner
	p.spawn_empty() // animator as child, using EntityWorldMut impl that this spawn_empty return
});

and what about directly a component that insert the animation ? instead of using entity commands