&nbsp; From a celebrated opera tenor to the Mexican revolution of 1910, PBS celebrates Hispanic Heritage 2010 with a strong slate of new and encore programming GREAT PERFORMANCES &ldquo;Placido Domingo: My Favorite Roles&rdquo; Friday, September 23, 2011, 9:00-10:30 p.m. ET, HD &nbsp;&nbsp;&nbsp; Placido Domingo is one of the most popular and celebrated tenors of his [...]