The Gene Siskel Film Center’s 29th annual festival of films from Iran kicks off this Saturday with “Mouth Harp in a Minor Key,” directed by Maryam Sepehri. We’re joined today by Sepehri and the subject of the film, Hamid Naficy, a historian of Middle Eastern and Iranian cinema and a filmmaker in his own right. The documentary centers on Naficy, who was exiled from Iran and now lives in Chicago, but he ultimately becomes a proxy for an entire generation of exiles and immigrants’ experiences with reconciling national and cultural identities away from their homelands.