Proactive Investors USA & CanadaUS STOCKS-Futures imply lower open after recent rallyReuters... * S&P 500, Nasdaq on six-day winning streak as of Tuesday. * Boeing rallies after results, outlook; P&G edges down. * Key earnings on tap; Apple, Facebook out after the close. * Futures down: Dow 14 pts, S&P 2.5 pts, Nasdaq 7.5 pts (Updates prices, adds ...U.S.