title: How to open incognito/private window with Selenium WD for different browser types?
body: <p>I want to test my test cases in <strong><em>private window</em></strong> or <strong><em>incognito window</em></strong>.</p>
  
  <p>How to do the same in various browsers:</p>
  
  <ul>
  <li>firefox (prefered) </li>
  <li>chrome (prefered) </li>
  <li>IE </li>
  <li>safari </li>
  <li>opera</li>
  </ul>
  
  <p><strong><em>How to achieve it?</em></strong>  </p>