Canadian officials on Sunday showed some optimism for the first time that they were beginning to get on top of the country's biggest wildfire, as cooler weather and light rain stopped the blaze from growing as much as feared and winds took the flames away from oil sands boomtown Fort McMurray."It definitely is a positive point for us, for sure," said Alberta fire official Chad Morrison in a news briefing, when asked if the fight to contain the flames had a reached a turning point."We're obviously very happy that we've held the fire better than expected," said Morrison. "This is great firefighting weather, we can really get in here and get a handle on this fire, and really get a death grip on it."The wildfire scorching through Canada's oil sands region in northeast Alberta had been expected to double in size on Sunday, threatening the neighboring province of Saskatchewan, as it moved into its seventh day.