adding label to navigation bar
if let navigationBar = self.navigationController?.navigationBar {
let firstFrame = CGRect(x: 0, y: 0, width: navigationBar.frame.width/2, height: navigationBar.frame.height)
let secondFrame = CGRect(x: navigationBar.frame.width/2, y: 0, width: navigationBar.frame.width/2, height: navigationBar.frame.height)
let firstLabel = UILabel(frame: firstFrame)
firstLabel.text = "First"
let secondLabel = UILabel(frame: secondFrame)
secondLabel.text = "Second"
navigationBar.addSubview(firstLabel)
navigationBar.addSubview(secondLabel)
}