    - parameter startingViewController: The currently selected view controller the transition is starting from
    - parameter destinationViewController: The view controller that will be scrolled to, where the transition should end
    */
-  optional func em_pageViewController(pageViewController: EMPageViewController, willStartScrollingFrom startingViewController: UIViewController, destinationViewController:UIViewController, direction: EMPageViewControllerNavigationDirection)
+  optional func em_pageViewController(pageViewController: EMPageViewController, willStartScrollingFrom startingViewController: UIViewController, destinationViewController:UIViewController)
   
   /**
    Called whenever there has been a scroll position change in a page transition. This method is very useful if you need to know the exact progress of the page transition animation.

  
  // MARK: - Internal Callbacks
  
  private func willScrollFromViewController(startingViewController: UIViewController?, destinationViewController: UIViewController, direction: EMPageViewControllerNavigationDirection) {
    if (startingViewController != nil) {
      self.delegate?.em_pageViewController?(self,
                                            willStartScrollingFrom: startingViewController!,
                                            destinationViewController: destinationViewController,
                                            direction: direction)
    }
    
    destinationViewController.beginAppearanceTransition(true, animated: self.transitionAnimated)

        // Scrolling reverse / before
      } else if (progress < 0) {
        if (self.beforeViewController != nil) {
          if !scrolling { // call willScroll once
            self.willScrollFromViewController(self.selectedViewController, destinationViewController: self.beforeViewController!)
            self.scrolling = true
          }
          
          if self.navigationDirection == .Forward { // check if direction changed
            self.didFinishScrollingToViewController(self.selectedViewController!)
            self.willScrollFromViewController(self.selectedViewController, destinationViewController: self.beforeViewController!)
          }
          
          self.navigationDirection = .Reverse
