Allow linking of contour map views

* Place copy of contour map in correct collection
* Allow linking of contour maps
* Improve handling of contour views and 3D views
* Guard nullptr
* Guard assert seen on Linux
* Zoom all on contour map when unlinked to reset zoom
If a contour map is linked to a 3D view, the view can get distorted. Call ZoomAll to reset to sensible defaults.

* Remove default rainbow legend

ApplicationLibCode/ModelVisualization/RivContourMapProjectionPartMgr.cpp

@@ -479,6 +479,9 @@ std::vector<cvf::ref<cvf::Drawable>>
                     {
                         for ( const cvf::BoundingBox& existingBBox : boxVector )
                         {
+                            // Assert on invalid bounding box seen on Linux
+                            if ( !displayBBox.isValid() || !existingBBox.isValid() ) continue;
+
                             double dist = ( displayBBox.center() - existingBBox.center() ).length();
                             if ( dist < segment.length() || existingBBox.intersects( displayBBox ) )
                             {