title: strtotime with year in 2 digit format
body: <p>Hallo can someone explain the behaviour of strtotime function with year in non-standard format. </p>
  
  <pre><code>echo date("d-m-Y",strtotime('02-12-10')) .'&lt;br&gt;'; //10-12-2002
  echo date("d-m-Y",strtotime('09.09.10')) .'&lt;br&gt;'; //02-09-2010 --How this is interpreted?
  
  
  echo date("d-m-Y",strtotime('02-12-2010')) .'&lt;br&gt;'; //02-02-2010
  echo date("d-m-Y",strtotime('09.09.2010')) .'&lt;br&gt;'; //09-09-2010
  </code></pre>
  
  <p>I wanted to convert strings of format dd.mm.yy(09.09.10) to datetime format.</p>