code: public JQMButton setBackButton(String text) {
          JQMButton button = new JQMButton(text);
          button.withBuiltInIcon(DataIcon.LEFT);
          setBackButton(button);
          return button;
      }
docs: Creates an auto back button with the given text and replaces the
  current left button, if any.
  
  @param text
  the the text for the button
  
  @return the created {@link JQMButton}