CANADA STOCKS-TSX down as oil, gold weigh on resource stocks

(Adds strategist comment, updates prices to close) By Alastair Sharp TORONTO, Sept 8 (Reuters) - Canada's main stock index fell on Monday as weaker commodities prices, including oil's drop below $100 a barrel, weighed on shares of energy and mining companies. Brent crude fell below the psychologically important $100 a barrel level before ending in three-digit territory, while gold also fell more than 1 percent to a three-month low. The Toronto index is dominated by resource st