"Dunesday"? "Doomsdune"? Whatever the nickname, cinema operators are bracing for a box office battle royale on Dec. 18. That's when two of this year's biggest movies - Disney's Marvel adventure "Avengers: Doomsday" and Warner Bros. and Legendary's sci-fi epic "Dune: Part III" - are scheduled to face off in theaters. On one hand, it's an [...]