Update of tracing

In CcnxForwardingStrategy (connect using "/NodeList/*/$ns3::CcnxL3Protocol/ForwardingStrategy/<trace>":
(interests)
- OutInterests

In Ccnx (connect using "/NodeList/*/$ns3::CcnxL3Protocol/<trace>":
(interests)
- InInterests
- DropInterests
(nacks)
- OutNacks
- InNacks
- DropNacks
(data)
- OutData
- InData
- DropData
diff --git a/helper/ccnx-stack-helper.cc b/helper/ccnx-stack-helper.cc
index 9699c38..6e2a411 100644
--- a/helper/ccnx-stack-helper.cc
+++ b/helper/ccnx-stack-helper.cc
@@ -200,8 +200,7 @@
   Ptr<CcnxL3Protocol> ccnx = CreateObject<CcnxL3Protocol> ();
   node->AggregateObject (ccnx);
 
-  ccnx->SetForwardingStrategy
-    (DynamicCast<CcnxForwardingStrategy> (m_strategyFactory.Create<Object> ()));
+  ccnx->SetForwardingStrategy (m_strategyFactory.Create<CcnxForwardingStrategy> ());
   
   for (uint32_t index=0; index < node->GetNDevices (); index++)
     {