LOS ANGELES (Reuters) - Making a comeback as Oscar host after an eight-year absence, comedian Billy Crystal poked fun on Sunday night at his own reluctance to return and paid light-hearted tribute to leading nominees for the 84th annual Academy Awards. In his ninth appearance as master of ceremonies, Crystal, 63, did his best to keep the live broadcast moving with a mix of one-liners, song and the kind of comic set pieces that have enshrined him as one of the most beloved of Oscar emcees. ...