By: Addison Wylie An after hours horror show goes mad in the uneven Late Night Double Feature.  Before the mayhem ensues on the set of Dr, Nasty’s Cavalcade of Horror, the audience is treated to a couple of spooky shorts intercut by commercials and previews. For the most part, the film is authentically structured like a craggy cable access show, which provides plenty of chuckles.  An ill-placed ad cashing in on the night’s horror theme…