Use non-arrow-function for export (#18)

* Use non-arrow-function for export

* Explicitly set arguments[0]

In strict mode, the elements in `arguments` are not the same ref as the actual arguments used in the function, editing one won't change the other.

[Useful MDN link](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Strict_mode#Making_eval_and_arguments_simpler)

* Add a comment about 'use strict'

lib/chai-exclude.js

@@ -1,6 +1,6 @@
 const fclone = require('fclone')
 
-module.exports = (chai, utils) => {
+module.exports = function (chai, utils) {
   const assert = chai.assert
   const Assertion = chai.Assertion
 
@@ -121,6 +121,9 @@ module.exports = (chai, utils) => {
         val = removeKeysFrom(val, props, true)
       }
 
+      // In case of 'use strict' and babelified code
+      arguments[0] = val;
+
       _super.apply(this, arguments)
     }
   }