THENS (Reuters) - The three Americans who made a clean sweep of the Olympic 200 metres medals took a diplomatic stance over the booing and jeering that delayed the start of their race. Once it finally got underway, Shawn Crawford led home Bernard Williams and 100 metres winner Justin Gatlin in a strange atmosphere in stark contrast to the carnival scenes that preceded the 100 metres final on Sunday. The 75,000 crowd at the Olympic Stadium booed and chanted "Kenteris" in frustration at the absence of Greek 2000 Olympic champion Costas Kenteris, who withdrew from the Games after missing a...