Fixed tests for node4

coverage/clover.xml

@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<coverage generated="1502298580285" clover="3.2.0">
-  <project timestamp="1502298580286" name="All files">
+<coverage generated="1502301711823" clover="3.2.0">
+  <project timestamp="1502301711823" name="All files">
     <metrics statements="32" coveredstatements="32" conditionals="18" coveredconditionals="18" methods="11" coveredmethods="11" elements="61" coveredelements="61" complexity="0" loc="32" ncloc="32" packages="1" files="1" classes="1">
       <file name="index.js" path="/Users/elliotmaincourt/Documents/Development/MifareJS/index.js">
         <metrics statements="32" coveredstatements="32" conditionals="18" coveredconditionals="18" methods="11" coveredmethods="11"/>

coverage/lcov-report/index.html

@@ -77,7 +77,7 @@ <h1>
 </div><!-- /wrapper -->
 <div class='footer quiet pad2 space-top1 center small'>
   Code coverage
-  generated by <a href="https://istanbul.js.org/" target="_blank">istanbul</a> at Wed Aug 09 2017 19:09:40 GMT+0200 (CEST)
+  generated by <a href="https://istanbul.js.org/" target="_blank">istanbul</a> at Wed Aug 09 2017 20:01:51 GMT+0200 (CEST)
 </div>
 </div>
 <script src="prettify.js"></script>

coverage/lcov-report/index.js.html

@@ -439,7 +439,7 @@ <h1>
 </div><!-- /wrapper -->
 <div class='footer quiet pad2 space-top1 center small'>
   Code coverage
-  generated by <a href="https://istanbul.js.org/" target="_blank">istanbul</a> at Wed Aug 09 2017 19:09:40 GMT+0200 (CEST)
+  generated by <a href="https://istanbul.js.org/" target="_blank">istanbul</a> at Wed Aug 09 2017 20:01:51 GMT+0200 (CEST)
 </div>
 </div>
 <script src="prettify.js"></script>

package.json

@@ -32,6 +32,7 @@
   "devDependencies": {
     "babel-core": "^6.25.0",
     "babel-eslint": "^7.2.3",
+    "babel-polyfill": "^6.23.0",
     "babel-preset-es2015": "^6.24.1",
     "babel-preset-stage-0": "^6.24.1",
     "eslint": "^4.4.1",