title: PyQt QtCharts Designer plugin
body: <p>I have tried the procedure (<a href="https://stackoverflow.com/questions/37869807/qt-charts-and-data-visualization-widgets">Qt Charts and Data Visualization widgets</a>) to integrate the qtchart plugin. 
  But it don't work. Makeing the plugin and add it to the desinger folder worked. qt designer ‎recognize the plugin but compiling the ui to a python file I get following error:</p>
  
  <p>Unknown Qt widget: QtCharts.QChartView</p>
  
  <p>I'm using linux with qt 5.7 and qtcharts and also pyqtcharts. </p>
  
  <p>I thing the problem is the 's' at the end of QtCharts, but I have no idea how I can fix it.</p>
  
  <p>Hope someone has a idea.</p>