title: Navigation bar titleView alignment
body: <p>I want my navigation bar to show two things in the middle. One them is going to be List name, and the other one will be name of users. User names will be placed under list name. What i have done so far is, i created two label and one superview programatically and set the <code>titleView</code> of <code>navigationItem</code>.</p>
  
  <pre><code>override func viewDidLoad() {
          super.viewDidLoad()
          var rectForView = CGRect(x: 0, y: 0, width: 190, height: 176)
          var viewForTitle = UIView(frame: rectForView)
  
          var rectForNameLabel = CGRect(x: 0, y: 63, width: 190, height: 30)
          var listNameLabel = UILabel(frame: rectForNameLabel)
          listNameLabel.text = "Name of the List...."
          listNameLabel.textAlignment = NSTextAlignment.Center
          listNameLabel.font = UIFont(name: "HelveticaNeue-Bold", size: 15)
  
          var rectForListLabel = CGRect(x: 0, y: 93, width: 190, height: 20)
          var usersOfListLabel = UILabel(frame: rectForListLabel)
          usersOfListLabel.text = "some Users...."
          usersOfListLabel.textAlignment = NSTextAlignment.Center
          usersOfListLabel.font = UIFont(name: "HelveticaNeue", size: 10)
  
          viewForTitle.addSubview(listNameLabel)
          viewForTitle.addSubview(usersOfListLabel)
  
  
          self.navigationItem.titleView = viewForTitle
  </code></pre>
  
  <p>The thing is, I'm picking width randomly, which leads to alignment problems in different devices. How to achieve middle alignment in my case?
  <img src="https://i.stack.imgur.com/JBuGq.png" alt="iphone 6"></p>
  
  <p><img src="https://i.stack.imgur.com/OyXto.png" alt="iphone 5"></p>