Consider a command to re-compute bounding volumes

[javagl]

Having tight-fitting bounding volumes can be an important quality criterion for tilesets. With the functions that have been introduced recently, and that allow computing the bounding volume of (nearly arbitrary) tile content, there could be a command line function like recomputeBoundingVolumes or so, that just goes through the (explicit) tile hierarchy, computes the bounding volumes of leaf tiles from their content, and the bounding volumes of inner tiles based on their content and child tile bounding volumes.