Add support for multiple curve sets in one VFP plot

- support selection of multiple values for multiple producer variables
- use one color for curves in a curve set representing a VFP curve collection
- use symbols to indicate individual family values for curves
- show all required values to identify curves as curve legend text and curve mouse hover text
- make sure all available settings of axis property object is applied to the plot axis
- support display of all curve data using "Show Plot Data"

ApplicationLibCode/ProjectDataModel/VerticalFlowPerformance/RimVfpPlotCollection.cpp

@@ -67,6 +67,7 @@ RimCustomVfpPlot* RimVfpPlotCollection::createAndAppendPlots( RimVfpTable* mainD
     auto vfpPlot = new RimCustomVfpPlot();
     vfpPlot->selectDataSource( mainDataSource, tableData );
     vfpPlot->initializeObject();
+    vfpPlot->initializeSelection();
 
     m_customVfpPlots.push_back( vfpPlot );