Onstage, gorgeous 'Once' has a heart all its own
There are plenty of romantic Broadway musicals. But "Once," the gorgeously crafted and intensely moving new show that opened on Broadway on Sunday night after a seamless transition from downtown to the main stem, is part of a much smaller and more rarefied group: musicals that are actually wise — even when that means being counterintuitive — about the joys and anguish of life and love, and that send the v…