all: InterestHeader and ContentObjectHeader refactoring to Interest and ContentObject

refs #29
diff --git a/model/pit/ndn-pit-impl.h b/model/pit/ndn-pit-impl.h
index bd86838..f3e49f9 100644
--- a/model/pit/ndn-pit-impl.h
+++ b/model/pit/ndn-pit-impl.h
@@ -75,13 +75,13 @@
 
   // inherited from Pit
   virtual Ptr<Entry>
-  Lookup (const ContentObjectHeader &header);
+  Lookup (const ContentObject &header);
 
   virtual Ptr<Entry>
-  Lookup (const InterestHeader &header);
+  Lookup (const Interest &header);
 
   virtual Ptr<Entry>
-  Create (Ptr<const InterestHeader> header);
+  Create (Ptr<const Interest> header);
 
   virtual void
   MarkErased (Ptr<Entry> entry);