FindNavigationBarTitleLabel.swift

  private func findTitleLabel() {
    let navBar = self.navigationController!.navigationBar
    let navigationItemView = navBar.subviews.filter { return String($0.dynamicType) == "UINavigationItemView" }[0]
    let titleLabel = navigationItemView.subviews.filter { return $0 is UILabel }[0] as! UILabel
    print("title label = \(titleLabel)")
  }