Issue 427 - Desugar arrow functions to normal or bound functions

autotest/abprewrite_source.js

 const Cc = Components.classes
 const Ci = Components.interfaces;
 const Cu = Components.utils;
 const Cr = Components.results;
 const Cl = Components.unknown;
 
 Cu.import("foo/bar.jsm");
 
 let {Timeline} = require("timeline");
 let {Utils} = require("utils");
@@ skipping 18 matching lines @@
   a += b;
   b -= a;
 }
 
 for (let [a, b] of fooList);
 
 for (k of fooList)
   alert(k);
 
 
-let a = function() 1;
+let a = function() { return 1 };
 let b = {
-  get foo() 1
+  get foo() { return 1; }
 };
 
 if (a == b)
   foo();
 else if (a == c)
   bar();
 else
   bas();
 if (a == b);
 
@@ skipping 16 matching lines @@
     yield i;
   }
 }
 var a = function()
 {
   for (var i = 0; i < 10; i++)
   {
     yield i;
   }
 };
+
+let x = (y) => y + 1;
+x = y => y + 1;
+x = (a, b) => this[a] + b;
+x = (a, b) => { return () => 1; }