Stephen Sondheim's darkly funny quasi-opera has been remounted as one of the year's biggest new productions If you seek Broadway's equivalent of Mount Rushmore, you could do worse than head to West 46th Street near Times Square. There you will find that Sweeney Todd, possibly the greatest stage musical of the 20th century, has pitched up across the street from Hamilton, probably the greatest of the 21st (so far). A q…
