As Philadelphia’s Chinatown fights a proposed casino mere feet from its doorstep, I’ve been thinking a lot these days about why saving Chinatown means so much to me. Several years ago my youngest son, who studied kung fu and Beijing Opera in Chinatown, told me: “My favorite place to be is Chinatown. I know everyone there. I can walk around and hang out. The guy in the laundromat always gives me candy and everyone knows I’m a lion dancer and the old people all smile at me