“What happens when the founding genius, the original voice, is gone? Martha Graham died in 1991, but her troupe survives, thanks to “contextual” presentations and new works by living choreographers; Paul Taylor, still actively producing work, is 85. His company, too, is making moves to widen its repertory. But the dance world often overlooks another company that has quietly gone about its business for decades in the absence of its founding choreographer, José Limón.”