(q-nor &rest args) constructs a UBDD representing the NOR of its arguments.
For instance:
(q-nor) = t (q-nor a) = (q-not a) (q-nor a b ...) = (q-not (q-or a b ...))
Macro: q-nor
(defmacro q-nor (&rest args) (cons 'q-not (cons (cons 'q-or args) 'nil)))
