By Martyn Herman RIO DE JANEIRO, Aug 15 (Reuters) - Australian track cycling great Anna Meares usually leaves scorch marks on velodrome boards. Meares won her sixth Olympic medal in Saturday's keirin final, a bronze, making her the first Australian to win an individual medal at four Games. While she has yet to officially announce that Rio will be her last Olympics, the body language of the 32-year-old daughter of a Queensland coalminer gave the game away. More...