Ash trays are at half-mast as the art world mourns the passing of one its finest and most innovative smokers, David Hockney, who has died at the age of 88. He died at home his publicist said, one cigarette short of his 89th that day. As a smoker Hockney always went his own way, famously rejecting a knighthood for services to tobacco and sticking to his quiet habit when others chose healthier routes. In 2018, one of his swimming pool paintings, 'Portrait of an Artist', sold fo