title: Difference between QPushButton and QToolButton
body: <p>I'm new to Qt and the difference between <code>QPushButton</code> and <code>QToolButton</code> is not so clear to me.</p>
  
  <p>I know that a <code>QToolButton</code> is usually used in a <code>QToolBar</code> and it usually shows only an icon, without text, but I don't quite understand the main difference between both. </p>
  
  <p>Does it have any bigger difference?
  When should I use <code>QPushButton</code> and when should I use <code>QToolButton</code>?</p>
  
  <p>I would like to know this to use the most appropriate button, and I need to perform some GUI tests and maybe it can be relevant.</p>