title: Listener for a Stage minimizing, maximizing, etc
body: <p>I am just starting my second JavaFX projects, and I need to know when a <code>Stage</code> is being maximized. In Swing, this is fairly simple and can be accomplished by using a WindowListener/Event. However, after searching through JavaFX's Javadoc, I can't seem to find any way of listening to the state of a <code>Stage</code>. </p>
  
  <p>Is there any way to do this? </p>