title: How to add bottom border to tableview section header
body: <p>I'm using the following function to determine the tableview section header in my app:</p>
  
  <pre><code>override func tableView(tableView: UITableView, viewForHeaderInSection section: Int) -&gt; UIView?{
      var title: UILabel = UILabel()
       title.text = "something" 
       // Add a bottomBorder
       var border = UIView(frame: CGRectMake(0,0,self.view.bounds.width,1))
       border.backgroundColor = UIColor.redColor()
       title.addSubview(border)
  }
  </code></pre>
  
  <p>and the following section to determine the tableview section header height:</p>
  
  <pre><code>override func tableView(tableView: UITableView, heightForRowAtIndexPath indexPath: NSIndexPath) -&gt; CGFloat
  </code></pre>
  
  <p>How can I add a bottom border to the section?</p>