The shadow of modern romance
A tableau on the Isle of the Dead. Photo: Gary Sloan.José Mateo remains as dependable as ever. His latest program, "Broken Shadows," (at the Sanctuary Theatre, near Harvard Square, through October 30) offers another tasty course of his specialty: that exquisite cross between modern dance and ballet which Balanchine brought to its highest pitch - and which has begun to fall from favor among the new genera…