(#396) Create main plot collection and well log plot collection if needed

Reading old project files may give projects without main plot collection
and well plot collection. Those are now created in the command feature
for adding a new well log plot, if needed.

ApplicationCode/ProjectDataModel/RimMainPlotCollection.h

@@ -37,7 +37,8 @@ public:
     RimMainPlotCollection();
     virtual ~RimMainPlotCollection();
 
-    caf::PdmChildField<RimWellLogPlotCollection*> wellLogPlotCollection;
+    RimWellLogPlotCollection* wellLogPlotCollection();
+    void recreateWellLogPlotCollection();
 
 protected:
 
@@ -46,7 +47,8 @@ protected:
 
 private:
     virtual caf::PdmFieldHandle* objectToggleField();
-
+    
 private:
+    caf::PdmChildField<RimWellLogPlotCollection*> m_wellLogPlotCollection;
     caf::PdmField<bool> show;
 };