* European stocks finish slightly higher; Wall Street flat* ECB&aposs Draghi promises more easing* Dollar regains traction, oil remains under pressure(Adds close of European markets)By Chuck MikolajczakNEW YORK, Nov 6 (Reuters) - The euro slumped to a two-year low and European government bond yields dipped on Thursday after European Central Bank chief Mario Draghi reiterated plans to revive the st