model: Major API changes

Interest and ContentObject are no longer derived from Header class.
Instead, they are encapsulating payload and, optionally, wire-formatted
Packet object.

Refs #1005 (http://redmine.named-data.net/)
diff --git a/model/fw/smart-flooding.cc b/model/fw/smart-flooding.cc
index 97faaf7..86ec8ee 100644
--- a/model/fw/smart-flooding.cc
+++ b/model/fw/smart-flooding.cc
@@ -66,14 +66,13 @@
 
 bool
 SmartFlooding::DoPropagateInterest (Ptr<Face> inFace,
-                                    Ptr<const Interest> header,
-                                    Ptr<const Packet> origPacket,
+                                    Ptr<const Interest> interest,
                                     Ptr<pit::Entry> pitEntry)
 {
   NS_LOG_FUNCTION (this);
 
   // Try to work out with just green faces
-  bool greenOk = super::DoPropagateInterest (inFace, header, origPacket, pitEntry);
+  bool greenOk = super::DoPropagateInterest (inFace, interest, pitEntry);
   if (greenOk)
     return true;
 
@@ -85,7 +84,7 @@
       if (metricFace.GetStatus () == fib::FaceMetric::NDN_FIB_RED) // all non-read faces are in the front of the list
         break;
 
-      if (!TrySendOutInterest (inFace, metricFace.GetFace (), header, origPacket, pitEntry))
+      if (!TrySendOutInterest (inFace, metricFace.GetFace (), interest, pitEntry))
         {
           continue;
         }