Bill Zito received a simple question when the Florida Panthers general manager met with the media Tuesday. “How?” he was asked. “Sorry?” he responded. “How?” “How?” “How did you do this?” Zito’s answer spoke volumes not only about himself but about the culture the back-to-back Stanley Cup champions have built -- a culture that led defenseman Aaron Ekblad and forwards Sam Bennett and Brad Marchand to stay instead of testing unrestricted free agency,