title: FB.getAccessToken() returns null until after I call FB.getLoginStatus() one time
body: <p>I'm making a very simple Facebook API request. I'm simply running:</p>
  
  <pre><code>FB.getAccessToken();
  </code></pre>
  
  <p>... and it's returning null every time. The moment I run:</p>
  
  <pre><code>FB.getLoginStatus();
  </code></pre>
  
  <p>... then FB.getAccessToken() <em>immediately</em> starts working and returning an access token every time.</p>
  
  <p>There's no code snippets to post because this happens even when I just do it from the JS console (which also means it can't be async issues).</p>