provide autoscale option for Qt plotting (bug #44307) * Canvas.h, Canvas.cc (Canvas::autoAxes): New pure virtual function. (Canvas::canvasAutoAxes): New function. (autoscale_axes): New static function. (Canvas::canvasMouseDoubleClickEvent, Canvas::canvasMousePressEvent): Use it. * Figure.h, Figure.cc (Figure::createFigureToolBarAndMenuBar): Add autoscale button to window. (Figure::autoAxes): New function. * GLCanvas.h, GLCanvas.cc (GLCanvas::autoAxes): New function.

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