title: UITableViewHeaderFooterView in InterfaceBuilder
body: <p>I want to create a custom header section view in a separate .xib using IB</p>
  
  <p>However in IB i cannot find a component UITableViewHeaderFooterView (similar to UITableViewCell) and assign a reuse for it</p>
  
  <p>So how to create in custom header section?</p>
  
  <p>I create a class MySection which inherits from UITableViewHeaderFooterView
  Create a .xib, MySection.xib
  Register xib for cell reuse</p>
  
  <p>the problem is, how to use the initWitReuseIdentifier....</p>