title: accessing user credentials/permissions
body: <p>Is there an easy way to get a credential/permission for a particular user?</p>
  
  <p>I've seen the <code>hasCredential()</code> method, but I'd like to dynamically check any user, not just the current user.</p>
  
  <p>I know I can use <code>sfContext::getInstance()-&gt;getUser();</code> to get the current user object, but is there a way to load in any user and get his/her credentials?</p>
  
  <p>Thanks</p>