Gate, Dublin Pam Gems' play may have dated, but the tragic arc of Édith Piaf from street urchin to torch singer is still compelling, told through music that rings with drama Edith Piaf's rise from singing on Paris streets to selling out Carnegie Hall is one of the great legends of musical stardom. In Des Kennedy's staging of Pam Gems' bio-musical, the focus is on the singer's decline and fall, her troubled life a…