By the time the toughest test in their five-game winning streak was winding down, the Detroit Pistons were making it look easy. Richard Hamilton scored 21 points, and the Pistons overcame an early 15-point hole before pulling away in a 91-76 victory over the New Orleans Hornets on Wednesday night. “When you play four games in five nights in four different cities, we were a little sluggish, but we…