Evidently not even Roald Dahl could resist the acronym craze of the early eighties. BFG? Bellowing ferret-faced golfer? Backstabbing fairy godmother? Oh, oh ... Big Friendly Giant! This BFG doesn't seem all that F at first as he creeps down a London street, snatches little Sophie out of her bed, and bounds away with her to giant land. And he's not really all that B when compared with his evil, …