LONDON (Reuters) - London drum'n'bass quartet Rudimental notched up a second number one in Britain's official singles charts on Sunday, at the expense of global stars Will.i.am and Justin Bieber who had to be content with the number two spot. Rudimental's song "Waiting All Night", featuring Ella Eyre, jumped straight to the top spot with 107,000 sales, beating Will.i.am's "#ThatPower", a collaboration with Bieber, by 38,000, the Official Charts Company said. Rudimental had achieved their first number one in 2012 with their summer anthem "Feel The Love". ...