GLOBAL MARKETS-Franc falls as Swiss go sub-zero; stocks jump after Fed

* Japanese shares lead most Asian markets higher* Fed pledges to be patient on withdrawing stimulus* Wall St racks up biggest daily gain this year* Treasury yields jump, give U.S. dollar a boostBy Marc JonesLONDON, Dec 18 (Reuters) - The Swiss franc tumbled on Thursday as its central bank slapped a charge on deposits, wary of a flood of money exiting Russia and the likely pressure from the euro zo