Remove Ugly Frame in 3d Plot

With v3 we have removed the sunken frames on
all the plots to make for a cleaner 'flat' feel
to the charts. The 3d plot has now been adjusted
to be in line with the rest of the plots.

src/ModelPlot.cpp

@@ -999,7 +999,7 @@ ModelPlot::ModelPlot(MainWindow *parent, ModelSettings *settings) : QFrame(paren
 
     layout = new QVBoxLayout;
     setLineWidth(1);
-    setFrameStyle(QFrame::Box | QFrame::Raised);
+    setFrameStyle(QFrame::NoFrame);
     setContentsMargins(0,0,0,0);
     basicModelPlot = new BasicModelPlot(parent, settings);
     layout->addWidget(basicModelPlot);