Asia stocks hold gains before Yellen speech, dollar firm

By Saikat Chatterjee HONG KONG (Reuters) - Asian stocks edged higher on Thursday but clung to recent well-worn trading ranges while the dollar held firm against regional currencies ahead of a speech by Federal Reserve Chair Janet Yellen at a global central bankers' meeting. MSCI's broadest index of Asia-Pacific shares outside Japan edged 0.3 percent higher. Japan's Nikkei was down 0.3 percent, pressured by losses on Wall Street overnight and investor caution ahead of Yellen's speech in Jackson H