split preparing clauses and writing problemfile;
included results of count_constants in return-type of prover;
optionally pass counted constants to prover;
removed unused external_prover from signature
(* Title: HOL/MetisExamples/ROOT.ML
ID: $Id$
Author: Lawrence C Paulson, Cambridge University Computer Laboratory
Testing the metis method.
*)
use_thys ["set", "BigO", "Abstraction", "BT", "Message", "Tarski", "TransClosure"];