Explosive Device Shatters North End Window Federal Investigators Called To Scene POSTED: 9:53 am EDT July 23, 2004 UPDATED: 12:23 pm EDT July 23, 2004 BOSTON -- With the Democratic Convention right around the corner, emergency responders got an early test Friday in Boston's North End when a small explosion in the Copps Hill cemetery gave neighbors quite a scare. NewsCenter 5's Gail Huff reported that the explosion occurred at about 8 a.m. in the graveyard near Snow Hill Street. It shattered a window in the Michael Angelo building, which is housing for the elderly. "It sounded like a bomb....