More progress on CCNx stack. Now we have helpers. Everything compiles, but not yet working

diff --git a/model/ccnx-interest-header.cc b/model/ccnx-interest-header.cc
index a7f2feb..6b322e2 100644
--- a/model/ccnx-interest-header.cc
+++ b/model/ccnx-interest-header.cc
@@ -25,6 +25,8 @@
 
 #include "ccnx-interest-header.h"
 
+#include "ns3/log.h"
+
 NS_LOG_COMPONENT_DEFINE ("CcnxInterestHeader");
 
 namespace ns3