AvatarJacob Thomas'Guardians of the Galaxy Vol. 2' Star Karen Gillan on Nebula's Future and a Female Doctor Whoverified_publisherMoviefoneIf you only know Doctor Who," last year's under-appreciated indie western "In a Valley of Violence," and "The Circle" (also currently in theaters), is charming, excitable, and very sweet, all of which makes her transformation into the revenge-seeking Nebula even more impressive. In "Guardians of the …