title: Understanding ons.slidingMenu variable in onsen-ui framework
body: <p>please explain me in a words why it works perfect when I call
  <code>ons.slidingMenu.toggleMenu()</code>
  having at the same time <code>myMenu</code> as variable of
  <code>&lt;ons-sliding-menu ....var="myMenu"&gt;</code></p>
  
  <p>I mean I should call <code>myMenu.toggleMenu()</code>, not <code>ons.slidingMenu.toggleMenu()</code> ....</p>
  
  <p>I think that ons.slidingMenu is defined deep inside onsen. Where I could read about all this hidden vars? (I've found nothing about it in onsen-ui site)</p>
  
  <p>Thanks!</p>