CANADA STOCKS-TSX slips as energy, gold shares tumble

* TSX down 89.91 points, or 0.59 percent, at 15,081.32 * Eight of 10 main index sectors decline * Oil-price fall weighs on energy shares By John Tilak TORONTO, July 15 (Reuters) - Canada's main stock index dropped on Tuesday amid a selloff in shares of energy and gold producers as investors focused on congressional testimony by U.S. Federal Reserve Chair Janet Yellen. Oil prices tumbled to a three-month low before recovering some of those losses as output from Libya increase