Labour set to take London after bitter mayoral campaign

By Elizabeth Piper and William James LONDON (Reuters) - Sadiq Khan, a Muslim opposition lawmaker, is on course to be elected London's mayor on Thursday, loosening the ruling Conservatives' hold on Britain's financial centre after a campaign marred by charges of anti-Semitism and extremism. The fight to run the British capital has pitted the Labour Party's Khan, 45, the son of a bus driver who grew up in public housing, against Conservative Zac Goldsmith, 41, the elite-educated son of a billionai