v0.2.55..v0.2.56 changeset NodesVisitor.h

diff --git a/hoot-core/src/main/cpp/hoot/core/visitors/NodesVisitor.h b/hoot-core/src/main/cpp/hoot/core/visitors/NodesVisitor.h
index 487676b..691b557 100644
--- a/hoot-core/src/main/cpp/hoot/core/visitors/NodesVisitor.h
+++ b/hoot-core/src/main/cpp/hoot/core/visitors/NodesVisitor.h
@@ -43,7 +43,8 @@ public:
 
   static std::string className() { return "hoot::NodesVisitor"; }
 
-  NodesVisitor(QList<ConstNodePtr>& n) : _n(n) {}
+  NodesVisitor(QList<ConstNodePtr>& n) : _n(n) { }
+  virtual ~NodesVisitor() = default;
 
   virtual void visit(const std::shared_ptr<const Element>& e);