The Hamptons International Film Festival announced some of its key films for this year’s event last week. On Oct. 6, it will open the festival in East Hampton with “Loving,” the story of the couple whose Supreme Court case did away with laws against interracial marriage in 1967. Directed and written by Jeff Nichols, it stars Joel Edgerton, Ruth Negga, Marton Csokas, Nick Kroll, and Michael Shannon.