added quick_and_dirty (from Isar/skip_proofs.ML);
added quick_and_dirty (from Isar/skip_proofs.ML);

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