WEIGHT-LOSS CHALLENGE CRYSTAL JONES LOST 52 LBS. THEN 231 LBS. When the interior designer, 27, walked down the aisle on Oct. 23, “my dress was a little big!” says Jones. She dropped from a size 18 to a 12, thanks to three-day-a-week workouts created by trainer Roma Simkute and a 1,200-calorie…