(Adds details, quotes) By Martyn Herman RIO DE JANEIRO, Aug 18 (Reuters) - Maris Strombergs criticised the Olympic BMX course after his hopes of a third consecutive gold medal were blown away in the accident-marred men's quarter-finals on Thursday. The Latvian, winner in Beijing and London, crashed heavily in the first run of his heat, tangling with Britain's former world champion Liam Phillips who took no further part. Reigning world champion and gold medal favourite Joris Daudet also crashed in the second of three runs in his heat. More...