recursion on item changes
rename and some other similiars should offer to work on all subitems too.
e.g. renaming the Item should rename subitems also to the new base
we have also to keep hierarchical acls. if the acl base of subitens becomes moved / renamed / killed we change also acl rights of subitems to default entries if nothing is set on subitems.
If hierarchical acls are used we should forbide moving the master without changing acls on all its subitems.