LOS ANGELES — At first glance, it might appear that Claire Danes and HBO are a little behind the curve with "Temple Grandin," a biopic about an early autistic advocate and educator. In the years since "Rain Man," autism has created something of a stock character in television and film. Indeed, when Danes was preparing for the role of Grandin, she had to look no further than her husband, Hugh Dancy, who recently starred in "Adam."