CANADA STOCKS-TSX clings to small gain despite Ukraine anxiety

* TSX up 16.01 points, or 0.11 percent, at 14,225.60 * Oil and gold shares rise with commodity prices By Leah Schnurr TORONTO, March 3 (Reuters) - Canada's main stock index firmed slightly on Monday as resource shares piggybacked higher on rising oil and gold prices in reaction to heightening tension between Russia and Ukraine. Ukraine said Russia was gathering armored vehicles on its side of a narrow stretch of water closest to Crimea after Russian President Vladimir Putin decl