title: How do you configure Qt Creator to use both Qt4 and Qt5?
body: <p>I download Qt Creator 2.7.0 (Based on Qt 5.0.2 (64 bit)).
  This seems to compile everything with Qt5.</p>
  
  <p>I know you can download the Qt4 SDK, but then how can i configure projects to use Qt4 instead if I need to? Please provide detailed instructions. I'm on Ubuntu and not using any repository supplied Qt tools/libraries.</p>