By Jonathan Lockwood For around a year Mezcal Spotlight has stayed politely close to home — local bars, local restaurants. Fine. But mezcal doesn't start in a bar. It starts in the ground, in fire, in a family argument about whose abuelo did it better. Cecilia and I have known the unbelievably sweet Alejandro and Bethy of Hacienda Vergel de Guadalupe for several years, but only a few weekends ago finally visited them at their hacienda in San Luis de la Paz, about an hour and