WRAPUP 4-Olympics-Bolt out to prove lightning can strike twice (Reuters)

(Adds Bolt quotes, latest golds, BMX) * Usain Bolt gunning for unique "double-double" * Briton becomes first woman Olympic boxing champion * Ireland's Katie Taylor also boxes to popular gold * United States catching up with China in medals haul LONDON, Aug 9 (Reuters) - Jamaican sprinter and world-recordholder Usain Bolt is out to prove that lightning can striketwice on Thursday when he seeks to defend his 200 metres title,while the United States closes in on China at the head of theOlympic medals table. ...