all: InterestHeader and ContentObjectHeader refactoring to Interest and ContentObject

refs #29
diff --git a/examples/custom-strategies/custom-strategy.cc b/examples/custom-strategies/custom-strategy.cc
index 5812ca3..05e7e83 100644
--- a/examples/custom-strategies/custom-strategy.cc
+++ b/examples/custom-strategies/custom-strategy.cc
@@ -44,7 +44,7 @@
 
 bool
 CustomStrategy::DoPropagateInterest (Ptr<Face> inFace,
-                                     Ptr<const InterestHeader> header,
+                                     Ptr<const Interest> header,
                                      Ptr<const Packet> origPacket,
                                      Ptr<pit::Entry> pitEntry)
 {
@@ -76,7 +76,7 @@
 
 void
 CustomStrategy::DidSendOutInterest (Ptr<Face> inFace, Ptr<Face> outFace,
-                                    Ptr<const InterestHeader> header,
+                                    Ptr<const Interest> header,
                                     Ptr<const Packet> origPacket,
                                     Ptr<pit::Entry> pitEntry)
 {