LOS ANGELES (May 18) - Councilman Antonio Villaraigosa trounced Mayor James Hahn to become the city's first Hispanic mayor in more than a century as voters turned to the promise of change in a metropolis troubled by gridlock, gangs and failing schools. Tuesday's election confirms the rising political power of Latinos in the nation's second-largest city. In a victory speech before thousands of supporters in downtown Los Angeles, Villaraigosa, 52, paid tribute to his heritage while promising to bring the city's diverse racial and ethnic groups together. ''I stand here today because people believed in me. I want you to...