Issue 427 - Desugar arrow functions to normal or bound functions

autotest/test_abprewrite_module.js.expected

 /*
  * This file is part of Adblock Plus <http://adblockplus.org/>,
  * Copyright (C) 2006-2014 Eyeo GmbH
  *
  * Adblock Plus is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 3 as
  * published by the Free Software Foundation.
  *
  * Adblock Plus is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 105 matching lines @@
   }
   var a = function()
   {
     var _generatorResult10 = [];
     for (var i = 0; i < 10; i++)
     {
       _generatorResult10.push(i);
     }
     return _generatorResult10;
   };
+  var x = function(y)
+  {
+    return y + 1;
+  };
+  x = function(y)
+  {
+    return y + 1;
+  };
+  x = function(a, b)
+  {
+    return this[a] + b;
+  }.bind(this);
+  x = function(a, b)
+  {
+    return function()
+    {
+      return 1;
+    };
+  }.bind(this);
   return exports;
 })();