Added a virtual destructor.
diff --git a/ndn-cpp/transport/transport.hpp b/ndn-cpp/transport/transport.hpp
index 4be901f..3246340 100644
--- a/ndn-cpp/transport/transport.hpp
+++ b/ndn-cpp/transport/transport.hpp
@@ -44,6 +44,8 @@
    * Close the connection.  This base class implementation does nothing, but your derived class can override.
    */
   virtual void close();
+  
+  virtual ~Transport();
 };
 
 }