added rule_attribute: ('a -> thm -> thm) -> 'a attribute; added tag / untag attributes;
added rule_attribute: ('a -> thm -> thm) -> 'a attribute;
added tag / untag attributes;

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