Conservatives unapologetic over tactics as Khan becomes London's first Muslim mayor

By Kate Holton LONDON (Reuters) - Sadiq Khan of the Labour Party was sworn in as Mayor of London on Saturday, becoming the first Muslim to head a major European capital after an election campaign marked by the Conservatives' efforts to link him to extremism. The son of a Pakistani immigrant bus driver and a seamstress, Khan defeated Conservative candidate Zac Goldsmith, the son of a billionaire financier, by a record margin to secure the biggest individual mandate in British political history. T