By TIM MADIGAN The story of Maxat Aitbayev began in a country most Americans probably couldn’t find on a map and ended a few weeks ago on a brilliant Sunday afternoon in Fort Worth. A small crowd gathered around a new mound of red clay at Oakwood Cemetery that day. They came to remember Maxat, who had turned 21 just a few weeks before, a remarkable young man who played piano and guitar, dominated at table tennis, loved little kids and was an eloquent writer.The mourners also came to support Rebekah Martin, the woman Maxat called Mama.