Changing to file level use strict statement

lib/axios.js

@@ -1,3 +1,5 @@
+'use strict';
+
 var defaults = require('./defaults');
 var utils = require('./utils');
 var deprecatedMethod = require('./helpers/deprecatedMethod');
@@ -6,8 +8,6 @@ var InterceptorManager = require('./core/InterceptorManager');
 
 // Polyfill ES6 Promise if needed
 (function () {
-  'use strict';
-
   // webpack is being used to set es6-promise to the native Promise
   // for the standalone build. It's necessary to make sure polyfill exists.
   var P = require('es6-promise');
@@ -17,8 +17,6 @@ var InterceptorManager = require('./core/InterceptorManager');
 })();
 
 var axios = module.exports = function axios(config) {
-  'use strict';
-
   config = utils.merge({
     method: 'get',
     headers: {},
@@ -73,7 +71,6 @@ axios.defaults = defaults;
 
 // Expose all/spread
 axios.all = function (promises) {
-  'use strict';
   return Promise.all(promises);
 };
 axios.spread = require('./helpers/spread');
@@ -86,8 +83,6 @@ axios.interceptors = {
 
 // Provide aliases for supported request methods
 (function () {
-  'use strict';
-
   function createShortMethods() {
     utils.forEach(arguments, function (method) {
       axios[method] = function (url, config) {