title: PyQt5 "xcb" not found
body: <p>I created an app with Qt designer. When I launching my app It throws this error:</p>
  
  <pre><code>This application failed to start because it could not find or load the Qt platform plugin "xcb"
  in "".
  
  Reinstalling the application may fix this problem.
  Aborted (core dumped)
  </code></pre>
  
  <p>Error throws then program executes this line:</p>
  
  <pre><code>app = QtWidgets.QApplication(sys.argv)
  </code></pre>
  
  <p>This is looks like there is some missing dependencies. <strong>How to fix this problem?</strong></p>
  
  <p>I tried to reinstall <code>libxcb</code>, but this didn't help.</p>
  
  <p><em>P.S.: I'm using manjaro linux and python 3.5.2</em>.</p>
  
  <p><em>P.P.S.: I get this error then tried to launch <code>ipython qtconsole</code></em></p>