Back from the Marines and two combat tours chasing the Taliban in the mountains of Afghanistan, Joseph Singer found more trouble than he ever expected just two blocks from home. Tuesday night, Singer, 22, and his father, Bruce Singer, 50, both of Revere, fended off an attack by knife and shovel-wielding punks that left the younger Singer stabbed in the gut. ``They were vicious, godless animals, that's what they were,'' Bruce Singer said yesterday. About 6:30 that night, Joe Singer was on his way home to have dinner with his dad when he saw some youths throwing chunks of ice...