make copying images to the clipboard work with Qt graphics * Figure.h, Figure.cc (Figure::createFigureToolBarAndMenuBar): Enable Copy item in the Edit menu. (delete_file): New static function. (Figure::copy_figure_callback): New member function. (Figure::editCopy): New arg, choose_format. Make it work.

<!DOCTYPE RCC><RCC version="1.0">
<qresource>
  <file>images/pan.png</file>
  <file>images/rotate.png</file>
  <file>images/select.png</file>
  <file>images/zoom-in.png</file>
  <file>images/zoom-out.png</file>
</qresource>
</RCC>