First, a confession: Open a film with a vast expanse of stars and you’ve instantly grabbed my inner geek by vice grip right where it counts. Put a knobby starship plowing through that expanse of stars to regions unknown and you’ve won my goodwill. Hello, Pandorum. As the most recent big screen addition to the grime-crusted house deep space sci-fi morphed into circa 1979, German director Christian Alvart’s Pandorum manages to kick off in disorienting fashion, nicely setting up unanswered …