Revert "Not using the deprecated / broken api (assuming that it was working before)"

This reverts commit 13ac655b1c256140f20be89e84c605e32feac580.

index.js

@@ -2,7 +2,7 @@
   "use strict";
 
   function atob(str) {
-    return new Buffer(str).toString('base64');
+    return new Buffer(str, 'base64').toString('utf8');
   }
 
   module.exports = atob;