title: Facebook PHP SDK: How to get session with Infinite SessionKey
body: <p>I need to get session and convert in into access_token, to work with profile via my local aplication.
  I can't get it working even old style:</p>
  
  <p>Generated here:
  <a href="http://www.facebook.com/code_gen.php?v=1.0&amp;api_key=YOUR_API_KEY" rel="nofollow">http://www.facebook.com/code_gen.php?v=1.0&amp;api_key=YOUR_API_KEY</a></p>
  
  <pre><code>require($this-&gt;_config-&gt;path-&gt;application . 'api/facebook.php');
  
  $facebook = new Facebook(array(
      'appId'  =&gt; $this-&gt;view-&gt;app_id,
      'secret' =&gt; $this-&gt;view-&gt;secret,
      'cookie' =&gt; true
  ));
  
  $old_rest_call_param = array(
      'method' =&gt; 'auth.getsession', 
      'auth_token'=&gt; '3GDWQG'
  );
  $allocation = $facebook-&gt;api($old_rest_call_param);
  </code></pre>
  
  <p>Getting "Invalid parameter" error on this request.</p>
  
  <p>I have tried on test console, it throws the same error:
  <a href="http://developers.facebook.com/docs/reference/rest/auth.getSession" rel="nofollow">http://developers.facebook.com/docs/reference/rest/auth.getSession</a></p>
  
  <p>Can't find any documentation / example about new way of getting infinite session usage.</p>
  
  <p>Anyone help please? ;)</p>