THOUSAND OAKS, California (Reuters) - California has been one of Graeme McDowell's happiest hunting grounds and he is delighted to be back in the 'Golden State' for this week's World Challenge. The Northern Irishman won his first major title in the 2010 U.S. Open at Pebble Beach in Northern California, then five months later he beat tournament host Tiger Woods in a playoff to clinch the World ...