all: InterestHeader and ContentObjectHeader refactoring to Interest and ContentObject

refs #29
diff --git a/apps/ndn-consumer.h b/apps/ndn-consumer.h
index 918d946..b748c2a 100644
--- a/apps/ndn-consumer.h
+++ b/apps/ndn-consumer.h
@@ -58,13 +58,13 @@
 
   // From App
   // virtual void
-  // OnInterest (const Ptr<const InterestHeader> &interest);
+  // OnInterest (const Ptr<const Interest> &interest);
 
   virtual void
-  OnNack (const Ptr<const InterestHeader> &interest, Ptr<Packet> packet);
+  OnNack (const Ptr<const Interest> &interest, Ptr<Packet> packet);
 
   virtual void
-  OnContentObject (const Ptr<const ContentObjectHeader> &contentObject,
+  OnContentObject (const Ptr<const ContentObject> &contentObject,
                    Ptr<Packet> payload);
 
   /**