LOS ANGELES — Jerry Lewis, the manic, rubber-faced showman who jumped and hollered to fame in a lucrative partnership with Dean Martin, settled down to become a self-conscious screen auteur and found an even greater following as the tireless, teary host of the annual muscular dystrophy telethons, has died. He was 91. Publicist Candi Cazau said Lewis died Sunday morning of natural causes in Las Vegas with his family by his side. Lewis’ career spanned the history of show business in the 20th century, beginning in his parents’ vaudeville act at the age of 5.