title: error: Unknown module(s) in QT: phonon
body: <p>I am beginner with Qt.<br>
  I installed Qt creator in Windows 7.<br>
  When I write <code>Qt += phonon</code> in <code>project.pro</code>, I meet with this error:  </p>
  
  <pre><code>error: Unknown module(s) in QT: phonon  
  </code></pre>
  
  <p>Can someone help me?</p>