If you’re a Star Wars fanatic, your thrusters are probably already in hyperdrive in anticipation of the release of the next installment of the franchise, “The Force Awakens,” which opened Thursday night. It is hard to imagine the films without the entire subculture of cosplay, props, toys, videogames, books and action-figures that come with them. But, alas, there did exist a time before wookies and droids and Han Solo. That’s where “St. Louis on the Air” host Don Marsh comes in.