There are 16 Tony Awards and 49 Broadway shows between Stephen Sondheim and Andrew Lloyd Webber, two of the most influential composers in the history of musical theater. On March 22, Lloyd Webber and Sondheim celebrated their birthdays. Sondheim, whose work in West Side Story and Company are on Broadway now, turned 90, and Lloyd Webber, the legendary composer of The Phantom of the Opera, turned 72. The pair mad…