Fix dateRangePicker to use provided language for value

This fix intents to correct issue longbill#193 by following suggestion on issue longbill#282

src/jquery.daterangepicker.js

@@ -870,6 +870,7 @@
     };
 
     $.fn.dateRangePicker = function(opt) {
+        moment.locale(opt.language);
         if (!opt) opt = {};
         opt = $.extend(true, {
             autoClose: false,
@@ -2586,4 +2587,4 @@
         }
 
     };
-}));
+}));