Mel Shavelson, a prolific radio, TV, and movie writer, and a director and producer of many of the films he wrote, died Wednesday in Los Angeles of natural causes at age 90. He received Oscar nominations for best screenplay in 1956 for The Seven Little Foys, which starred Bob Hope as vaudevillian Eddie Foy, and two years later for Houseboat, which starred Cary Grant and Sophia Loren. His autobiography, published on his 90th birthday on April 1, was titled How to Succeed in Hollywood Without Really Trying, P.S. -- You Can't.