James Cameron has shored up his position as king of the worldwide box office. Cameron's 1997 blockbuster "Titanic" sailed beyond the $2 billion mark in lifetime ticket sales, thanks to a 3-D re-release of the film that was timed to the centennial of the ship's sinking. Only one other movie has topped $2 billion, and it's also Cameron's. His 2009 sci-fi smash "Avatar" earned $2.8 billion worldwide. The "Titanic" reissue took in about $100 million this weekend – $11.6 million domestically and a...