title: toDateString() decrements my date
body: <p>For the following code:</p>
  
  <pre><code>var d = new Date("2013-07-01");
  console.log(d.toDateString());
  </code></pre>
  
  <p>It outputs Sun Jun 30 2013, which is one day less of what was input. What happened to the object? What date is actually stored?</p>