     private var horizontalConstraints: [NSLayoutConstraint] = []
     
     private let albumListViewController = AlbumListTableViewController()
-    private var isPresentingAlbumListView: Bool = false
     
     override func loadView() {
         super.loadView()

                self.albumListViewController.view.alpha = 1.0
                self.imageView.willMoveToSuperview(self.vibrancyEffectView)
            }) { _ in
                    self.albumListViewController.didMoveToParentViewController(self)
                    self.isPresentingAlbumListView = true
            }
        }
    }
    
    
    override func updateViewConstraints() {
        if self.view.traitCollection.verticalSizeClass == .Regular {
            horizontalConstraints.forEach   { $0.active = false }
            verticalConstraints.forEach     { $0.active = true }
        } else {
            verticalConstraints.forEach     { $0.active = false }
            horizontalConstraints.forEach   { $0.active = true }
        }
        super.updateViewConstraints()
    }
    
    func updateCurrentTrack() {
        guard let songItem = musicPlayer.nowPlayingItem else { return }
        

    override func viewDidLoad() {
        super.viewDidLoad()
        
        let tapGesture = UITapGestureRecognizer(target: self, action: "tapGestureRecognizerFired:")
        self.view.addGestureRecognizer(tapGesture)
        
        playPauseButton.setImage(UIImage.Asset.Play.image, forState: .Normal)
        playPauseButton.addTarget(self, action: "togglePlayOrPause", forControlEvents: .TouchUpInside)
