BOSTON (Reuters) - Thousands of music fans clogged a Boston street on Monday to hear Grammy award-winning rock band Aerosmith perform a free concert in front of the apartment building where the musicians began their career four decades ago. The band blared out hits including "Walk This Way" and "Sweet Emotion" from the back of a specially converted tractor-trailer while area residents hung out windows, sat on balconies and stood on rooftops to hear the noontime concert. "It feels like the world stood still for this. ...