all: InterestHeader and ContentObjectHeader refactoring to Interest and ContentObject

refs #29
diff --git a/model/pit/ndn-pit.h b/model/pit/ndn-pit.h
index f8eeafb..1968bd4 100644
--- a/model/pit/ndn-pit.h
+++ b/model/pit/ndn-pit.h
@@ -32,8 +32,8 @@
 
 class L3Protocol;
 class Face;
-class ContentObjectHeader;
-class InterestHeader;
+class ContentObject;
+class Interest;
 
 ////////////////////////////////////////////////////////////////////////
 ////////////////////////////////////////////////////////////////////////
@@ -74,7 +74,7 @@
    *          returns 0
    */
   virtual Ptr<pit::Entry>
-  Lookup (const ContentObjectHeader &header) = 0;
+  Lookup (const ContentObject &header) = 0;
 
   /**
    * \brief Find a PIT entry for the given content interest
@@ -83,7 +83,7 @@
    *          return end() iterator
    */
   virtual Ptr<pit::Entry>
-  Lookup (const InterestHeader &header) = 0;
+  Lookup (const Interest &header) = 0;
 
   /**
    * @brief Creates a PIT entry for the given interest
@@ -94,7 +94,7 @@
    * Note. This call assumes that the entry does not exist (i.e., there was a Lookup call before)
    */
   virtual Ptr<pit::Entry>
-  Create (Ptr<const InterestHeader> header) = 0;
+  Create (Ptr<const Interest> header) = 0;
   
   /**
    * @brief Mark PIT entry deleted