W&M Bar-B-Q Burger   W&M opens at 10 a.m., and the eight parking stalls immediately fill up. Locals crave the cult burgers no matter what time it is. The nostalgic favorite isn't anything fancy premade patties on a Love's bun. It's the subtly sweet sauce that the burgers are soaked in that hooks people. That, and the Proustian moment we get every time we take a first bite.  3104 Waialae Ave., 734-3350. 10 a.m.-4:30 p.m. Wednesdays-Fridays; 9 a.m.-4:30 p.m. Saturdays-Sundays. $