add helpers

lib/6to5/helpers/object.js

@@ -0,0 +1,5 @@
+"use strict";
+
+module.exports = function () {
+  return Object.create(null);
+};

lib/6to5/util.js

@@ -25,10 +25,6 @@ exports.isInteger = function (i) {
   return _.isNumber(i) && i % 1 === 0;
 };
 
-exports.object = function () {
-  return Object.create(null);
-};
-
 exports.resolve = function (loc) {
   try {
     return require.resolve(loc);