Two years ago J.J. Abrams accepted an unenviable challenge: reboot Star Trek. It was a formidable undertaking on several frontiers (forgive me). Not only did Abrams have to appease a notoriously protective fan-base, but he also had to attract a generation of cinema-goers who had never even seen an episode of Trek. People who wouldn't know a Klingon's forehead corrugations from a Ktarian's. People who wouldn't care...