Added infrastructure for simplifying equality constraints.
Option (no_simp) restores old behaviour of induct method.
(* ID: $Id$
To update:
cp /home/lcp/isabelle/Repos/HOL/Auth/{Message.thy,Message_lemmas.ML,Event.thy,Event_lemmas.ML,Public.thy,Public_lemmas.ML,NS_Public.thy} .
*)
use_thy "NS_Public";