title: doctrine 2.0 : use SQL timestamp
body: <p>I'm looking for a way to make doctrine using <code>TIMESTAMP</code> instead of <code>DATETIME</code> for MySql.</p>
  
  <p>Additionaly I need to set <code>ON UPDATE CURRENT_TIMESTAMP</code> and <code>CURRENT_TIMESTAMP</code> as default values.</p>
  
  <p>I would like to have the possibility to have all this code in PHP annotations to have everything in one central place.</p>
  
  <p>How can I do that?</p>