CBC News.  The Conference Board of Canada says uncertainty over new pipeline projects poses a threat to Canadian companies that provide services to oil and gas producers. The Ottawa-based think-tank predicts the sector's real economic output this year will drop slightly by $60 million, or half a per cent, to $11.55 billion.  It says some of that is due to a lingering weakness in natural gas prices and a levelling off in conventional oil drilling.  The board says the "bigger threat" is the lack of pipeline capacity, as environmental opposition [...]