A TEENAGER with a “history of showing off” killed three of his pals in a horror crash, a court heard. Edward Spencer, now 19, was driving a Ford Fiesta near Shipston, Warwickshire, when he smashed into a Fiat 500, killing Harry Purcell, 17, Matilda “Tilly” Seccombe, 16, and Frank Wormald, 16. Spencer, who was 17 at the time, was driving his pals…