CHICAGO — It didn't matter that the 13 Marines on their way home from Afghanistan had been fighting in a war that no longer dominates the news or that they were stopping only for a short time in Chicago before flying to San Diego.When USO volunteer John Colas heard with just an hour's notice that the Marines' plane was bearing down on Chicago's O'Hare International Airport, he and others scrambled to make sure they got a hero's welcome.