eliminated slightly odd get/set operations in favour of Unsynchronized.ref;
eliminated aliases of Output operations;
print_cert: use warning for increased chance that the user actually sees the output;
misc tuning and simplification;
(* Title: Sequents/ROOT.ML
ID: $Id$
Author: Lawrence C Paulson, Cambridge University Computer Laboratory
Copyright 1991 University of Cambridge
Classical Sequent Calculus based on Pure Isabelle.
*)
use_thys ["LK", "ILL", "ILL_predlog", "Washing", "Modal0", "T", "S4", "S43"];