title: cakephp $this->params not set in beforeFilter
body: <p>I needed to do something with $this->params in the <code>AppController::beforeFilter()</code> I get <code>Notice (8): Undefined variable: a</code> but when I set it in <code>beforeFilter()</code> the <code>b</code> variable is set normally. Is this normal behavior? And if it isn't, how do I get the params to be set in <code>beforeFilter()</code>? It would have been better if I could work with the params before any action is called.</p>
  
  <pre><code>function beforeFilter() {
  $this-&gt;set('a', $this-&gt;params);
  }
  
  function beforeRender() {
  $this-&gt;set('b', $this-&gt;params);
  }
  </code></pre>