Luke HolwerdaCalexico's Joey Burns sings at the band's show Saturday at Heritage Square. See more shots in our Calexico slide show.There's one word that describes the Calexico concert at Heritage Square last night: Classy. From the tastefully-appointed stage, to the home-made tamales and high-end beer (Tecate and Four Peaks products only; no Bud) to the gorgeous textures of the band's unique blend of Western and Tejano music and indie rock, it was a show that felt more like the best wedding rece