added export_assume, export_presume, export_def (from proof.ML);
added export_assume, export_presume, export_def (from proof.ML);

MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle