David Staller, the artistic director of the Gingold Group, has made his mission to celebrate the plays of George Bernard Shaw. To that end, the group offers readings of Shaw plays monthly and hosts discussions about him. One play each year receives a fully staged production. The current offering, Caesar and Cleopatra, is a rarity. Although it’s interesting, it’s less satisfying than, for instance, its low-budget Heartbreak House was last season.