title: Get the naviagion-bar Left Button click
body: <p>With OnsenUI 1.0.4 I used this command ons.navigator.getCurrentPage().options.onLeftButtonClick to get the click event(string) for the left button from navigation bar.</p>
  
  <p>In OnsenUI 1.1.x I changed my project to use the ons-toolbar.
  How do I get the left button now?</p>
  
  <p>Thank you</p>