ndnSIM-v2: Initial implementation

- Name, name::Components, Interest, Data now use ndn-cxx
- Ptr is replaced with shared_ptr for ndn-cxx structures

Credits for the change also to Mickey Sweat, Wentao Shang, and Alex Afanasyev
diff --git a/utils/tracers/l2-tracer.hpp b/utils/tracers/l2-tracer.hpp
index a2cd3a6..814a860 100644
--- a/utils/tracers/l2-tracer.hpp
+++ b/utils/tracers/l2-tracer.hpp
@@ -21,6 +21,8 @@
 #ifndef L2_TRACER_H
 #define L2_TRACER_H
 
+#include "ns3/ndnSIM/model/ndn-common.hpp"
+
 #include "ns3/ptr.h"
 #include "ns3/simple-ref-count.h"
 #include "ns3/packet.h"