model: Another set of refactoring/renaming to make code compile (not tested yet)

Refs #1005 (http://redmine.named-data.net/)
diff --git a/examples/custom-apps/hijacker.h b/examples/custom-apps/hijacker.h
index 07185de..a90166d 100644
--- a/examples/custom-apps/hijacker.h
+++ b/examples/custom-apps/hijacker.h
@@ -39,7 +39,7 @@
 
   // Receive all Interests but do nothing in response
   void
-  OnInterest (const Ptr<const ndn::Interest> &interest, Ptr<Packet> packet);
+  OnInterest (Ptr<const ndn::Interest> interest);
 
 protected:
   // inherited from Application base class.