model: A basic implementation of ndn::ApiFace that can be used as an NDN handler in any "normal" NS-3 application

Refs #1005 (http://redmine.named-data.net/)
diff --git a/apps/ndn-producer.h b/apps/ndn-producer.h
index 1563d12..42f65aa 100644
--- a/apps/ndn-producer.h
+++ b/apps/ndn-producer.h
@@ -60,6 +60,7 @@
 
 private:
   Name m_prefix;
+  Name m_postfix;
   uint32_t m_virtualPayloadSize;
   Time m_freshness;
 };