It's a good thing Leonardo DiCaprio made so much money from "Titanic" a decade ago. His environmental documentary, "The 11th Hour," has been a total bust at the box office. After 18 days in release, the film has grossed only $417,913 from ticket sales. The 90-minute snore-fest is playing on 111 screens this week, but that number is likely to be reduced this Friday. The film will be sent to DVD heaven after that. By comparison, Al Gore and Davis Guggenheim's similar but far more engaging "An Inconvenient Truth" had already made $3.5 million by its 18th day of release....