title: UILabel not aligning perfectly center when wrapping
body: <p>See image for example: <a href="http://img25.imageshack.us/img25/6996/90754687.png" rel="nofollow noreferrer">http://img25.imageshack.us/img25/6996/90754687.png</a><br>
  The grey background indicates the size of the UILabel frame. </p>
  
  <p>For some reason, the first line of wrapped text doesn't seem to always center, even though I'm using UITextAlignmentCenter.</p>
  
  <p>Here's the code I use to set up my labels:</p>
  
  <pre><code>    self.titleLabel = [[UILabel alloc] initWithFrame:CGRectZero];
      titleLabel.font = [UIFont boldSystemFontOfSize:fontHeight];
      titleLabel.backgroundColor = [UIColor grayColor];
      titleLabel.numberOfLines = 2;
      titleLabel.lineBreakMode = UILineBreakModeMiddleTruncation;
  
      NSString * title = file.name;
      CGSize maximumSize = CGSizeMake(thumbnailWidth+4,fontHeight * 3);
      UIFont * font = [UIFont boldSystemFontOfSize:12];
      CGSize stringSize = [title sizeWithFont:font constrainedToSize:maximumSize lineBreakMode:titleLabel.lineBreakMode];
  
      CGRect stringFrame = CGRectMake(0, thumbnailHeight + thumbnailPadding, thumbnailWidth + 4, stringSize.height);
      titleLabel.text = title;
      titleLabel.frame = stringFrame;
      titleLabel.textAlignment = UITextAlignmentCenter;
  </code></pre>