Nikkei hits 6-mth high on earnings hopes; casino plays outperform

* Nikkei advances 0.5 pct, Topix up 0.4 pct * Expectations for domestic earnings lift market * Casino-related shares jump By Tomo Uetake TOKYO, July 28 (Reuters) - Japan's Nikkei average rose to six-month highs on Monday, and looked poised to test key resistance levels around 15,500 points, on hopes of continued improvement in corporate earnings. By the middday break, the benchmark Nikkei was up 0.5 percent at 15,530.29, its highest level since Jan. 23, reversing early losse