it is a good age for him to be.Boyd, 61, a winner of the Whitbread and Costa book prizes, follows writers including Kingsley Amis and Sebastian Faulks as a successor to Fleming, who died in 1964.His novel is authorized by the Fleming estate, and was launched Wednesday with fanfare befitting a major British cultural export.Boyd posed gamely for a photo call ??? at the Dorchester, naturally ??? alon