Hemingway Inspired by War, Not Booze, Depression

D T Max article on Ernest Hemingway's misadventures in Cuba in 1940's, based on newly-available papers explaining period when he left literary world and isolated himself from anyone who knew him as he really was; tells of self-imposed exile when Hemingway confused his fantasy self, man of action, with his real self, man who wrote about action, and embarked on parody of his previous wartime adventures as World War II heated up around him; photo; describes Finca Vigia, home outside Havana that is run by Cuban Government as shrine to Papa (M)