Doctor Who fans will get a double-dose of their hero for Christmas. BBC America will follow the previously announced Doctor Who Christmas special, Twice Upon A Time, with an all-new special Doctor Who: Farewell to Peter Capaldi. The announcement was made with the release of a new Twice Upon a Time trailer. Narrated by actor Colin McFarlane (The Dark Knight, Doctor Who), the Farewell show will feature archive footage and interviews, looking back at Capaldi’s era as the…