title: UINavigationBar TitleView with subtitle
body: <p>I want a titleView inside my UINavigationBar which has two lines of text instead of only one</p>
  
  <p>My current implementiation works well when I have a "Back"-Button and an "Edit" Button because it looks nearly centered. The problem is when I only have one of the Buttons. It looks really weird and wrong because the view centers itself on the available space. </p>
  
  <p><a href="http://twitpic.com/b4nxq7" rel="noreferrer">UINavigationBar with left and right Button</a></p>
  
  <p><a href="http://twitpic.com/b4ny7t" rel="noreferrer">UINavigationBar with only one Button</a></p>
  
  <p>This is my current implementation:</p>
  
  <pre><code>CGRect frame = self.navigationController.navigationBar.frame;
  
  UIView *twoLineTitleView = [[UIView alloc] initWithFrame:CGRectMake(CGRectGetWidth(frame), 0, CGRectGetWidth(frame), CGRectGetHeight(frame))];
  
  UILabel *titleLabel = [[UILabel alloc] initWithFrame:CGRectMake(0, 8, CGRectGetWidth(frame), 14)];
  titleLabel.backgroundColor = [UIColor clearColor];
  titleLabel.autoresizingMask = UIViewAutoresizingFlexibleWidth;
  titleLabel.textAlignment = UITextAlignmentCenter;
  titleLabel.text = self.title;
  [twoLineTitleView addSubview:titleLabel];
  
  UILabel *subTitleLabel = [[UILabel alloc] initWithFrame:CGRectMake(0, 23, CGRectGetWidth(frame), 14)];
  subTitleLabel.backgroundColor = [UIColor clearColor];
  subTitleLabel.autoresizingMask = UIViewAutoresizingFlexibleWidth;
  subTitleLabel.textAlignment = UITextAlignmentCenter;
  subTitleLabel.text = self.subTitle;
  [twoLineTitleView addSubview:subTitleLabel];
  
  self.navigationItem.titleView = twoLineTitleView;
  </code></pre>