CANADA STOCKS-TSX firm as copper producers slip but energy shares gain

* TSX up 27.42 points, or 0.18 percent, at 15,536.81 * Five of 10 main index sectors rise * First Quantum, Teck drop with copper price (Adds details, quotes, updates prices) By John Tilak TORONTO, Sept 9 (Reuters) - Canada's main stock index edged higher on Tuesday, snapping a three-day losing streak as gains in the heavyweight energy and financial sectors offset shares of commodity producers that were driven lower by weak copper prices. With the price of copper dropping mo