GLOBAL MARKETS-Oil slumps to four-year low as OPEC shuns output cut

* Oil hits $70 a barrel as OPEC shuns cut* European shares buoyed by ECB bond-buying hopes* French 10-yr govt bond yield hits 1 percent for first time* Asian shares edge up, helped by stimulus around the worldBy Marc JonesLONDON, Nov 27 (Reuters) - Oil hit four-year lows around $70 a barrel on Thursday and commodity currencies were sent tumbling, as OPEC resisted the temptation to cut back product