title: What is the difference between 'tableView.contentSize' and 'tableView.frame.size'
body: <pre><code>tableView.setContentOffset(CGPointMake(0, tableView.contentSize.height - tableView.frame.size.height), animated: true)
  </code></pre>
  
  <p>It works, but I wonder what actually are those two values:
  <code>tableView.contentSize</code>, <code>tableView.frame.size</code></p>