added "explicit_apply" option to Sledgehammer, to control whether an explicit apply function should be used as much or as little as possible (replaces a previous global variable)
(* Title: FOLP/ROOT.ML
Author: Martin Coen, Cambridge University Computer Laboratory
Copyright 1993 University of Cambridge
Modifed version of Lawrence Paulson's FOL that contains proof terms.
Presence of unknown proof term means that matching does not behave as expected.
*)
use_thys ["FOLP"];