Combine BoundedSpatialIndex with SpatialIndex

Issue #50 resolved
Michael Ludwig
repo owner created an issue

There is no need for two of these interfaces, indices that don't have a spatial bound can ignore the parameter to set it, and getBounds() can have a documented return value for unbounded.

Also a BoundsResult should be added to the math.entreri package so that the scene and physics types don't have to duplicate result. It should be made not singular, and should take a component type that represents the source of the unioned bounds so we can differentiate between them.