title: force cakephp 3 auth->user() to show virtual fields
body: <p>I have a user entity with accessor</p>
  
  <pre><code>namespace App\Model\Entity;
  use Cake\ORM\Entity;
  use Cake\Auth\DefaultPasswordHasher;
  class User extends Entity {
     protected $_accessible = [
         'email' =&gt; true,
         'username' =&gt; true,
         'password' =&gt; true,
     ];
     protected function _getFullname() {
         return $this-&gt;_properties['firstname'] . '  ' .$this-&gt;_properties['lastname'];
     }
  }
  </code></pre>
  
  <p>when I print</p>
  
  <pre><code>$user-&gt;fullname
  </code></pre>
  
  <p>in view it works properly
  but how can I get fullname in result of</p>
  
  <pre><code>pr($this-&gt;Auth-&gt;user());
  </code></pre>