(#437) Using MD or TVD depth values for well log extraction curves

Also renamed some methods for clarity, and fixed a bug in
RimWellLogPlot::updateViewerWidget(). Using this method instead of
loadDataAndUpdate() when toggling visibility of the plot.

ApplicationCode/ProjectDataModel/RimWellLogExtractionCurve.h

@@ -38,6 +38,7 @@ class RimWellLogExtractionCurve : public RimWellLogPlotCurve
 public:
     RimWellLogExtractionCurve();
     virtual ~RimWellLogExtractionCurve();
+    
     virtual void updatePlotData();
 
 protected: