title: Extend Yii2's BaseYii class to add static methods
body: <p>Is it possible to extend Yii2's BaseYii class, so I could add a static method similar to <code>Yii::t()</code> like this: <code>Yii::my_super_method()</code>?</p>
  
  <p>Can't really find any documentation about that, maybe I missed it.</p>