Buick is pulling out all the stops in attempting to shed the built-for-septuagenarians image it cultivated for a good two decades. Color us impressed: This new Verano has a turbo four-cylinder engine boasting 250 horsepower and 260 lb.-ft. of torque, and, heavens to Betsy, a proper three-pedals-and-a-stick manual transmission. That stick, we should add, is only available with the hot-spec …