Ex-Klansman Is Found Guilty In '63 Bombing
Thomas E Blanton Jr, now 62, is convicted in Birmingham of murdering four black girls in 1963 bombing of 16th Street Baptist Church, and is sentenced to four terms of life in prison; photos; former Ku Klux Klansman is second of four original suspects convicted; both sides seem stunned by speed of verdict, after two hours of deliberation; defense plans appeal; federal prosecutor Doug Jones is jubilant; surviving relatives comment (M)