extended addsplits and delsplits to handle also split rules for assumptions
extended const_of_split_thm, renamed it to split_thm_info
(* Title: ZF/upair.thy
ID: $Id$
Author: Lawrence C Paulson and Martin D Coen, CU Computer Laboratory
Copyright 1993 University of Cambridge
Dummy theory, but holds the standard ZF simpset.
*)
upair = ZF