LOS ANGELES — The sisters tried to stay strong all those years of being taunted as “ghosts” for the color of their skin, of being beaten by their teachers – of an attack that almost killed one of them. There was a dream, after all, at the end of the torturous road that began in their tiny African village: getting an education. Born albinos, Bibi and Tindi Mashamba missed so much school in their native Tanzania after an attack left Bibi without a leg and two fingers.