Retrieves hierarchy trees rooted by a given node (unless orphan is
specified -- See below)
This method also retrieves the Experimenters linked to the objects in the
tree. Similarly, all Images will be linked to their Pixel objects if
included.
Note that objects are never duplicated. For example, if an Experimenter
owns all the objects in the retrieved tree, then those objects will be
linked to the same instance of
ome.model.meta.Experimenter. Or if an
Image is contained in more than one Dataset in the retrieved tree, then
all enclosing
ome.model.containers.Dataset objects will point
to the same
ome.model.core.Image object. And so on.