Moving around path weight tagging. Now CcnxFace owns metric field, which is used for tagging.

Correcting bugs in blackhole-sprint scenario.  This time it should be
the right one:
- instead of a hijacker app, all faces on hijacked node are turned down
- there was a trick with RTT estimation (when batch, it is necessary to
  reset history upon a new batch)
- instead of random runs, trying all possible combinations of
  producer/hijacker
diff --git a/model/ccnx-face.h b/model/ccnx-face.h
index 29ec371..e2100c6 100644
--- a/model/ccnx-face.h
+++ b/model/ccnx-face.h
@@ -111,19 +111,19 @@
   Receive (const Ptr<const Packet> &p);
   ////////////////////////////////////////////////////////////////////
 
-  // /**
-  //  * \Brief Assign routing/forwarding metric with face
-  //  *
-  //  * \param metric configured routing metric (cost) of this face
-  //  */
-  // virtual void SetMetric (uint16_t metric);
+  /**
+   * \Brief Assign routing/forwarding metric with face
+   *
+   * \param metric configured routing metric (cost) of this face
+   */
+  virtual void SetMetric (uint16_t metric);
 
-  // /**
-  //  * \brief Get routing/forwarding metric assigned to the face
-  //  *
-  //  * \returns configured routing/forwarding metric (cost) of this face
-  //  */
-  // virtual uint16_t GetMetric (void) const;
+  /**
+   * \brief Get routing/forwarding metric assigned to the face
+   *
+   * \returns configured routing/forwarding metric (cost) of this face
+   */
+  virtual uint16_t GetMetric (void) const;
 
   /**
    * These are face states and may be distinct from actual lower-layer
@@ -228,7 +228,10 @@
   ProtocolHandler m_protocolHandler; ///< Callback via which packets are getting send to CCNx stack
   bool m_ifup; ///< \brief flag indicating that the interface is UP 
   uint32_t m_id; ///< \brief id of the interface in CCNx stack (per-node uniqueness)
-  Time m_lastLeakTime; 
+  Time m_lastLeakTime;
+  uint32_t m_metric; ///< \brief metric of the face
+
+  bool m_enableMetricTagging; 
 };
 
 std::ostream& operator<< (std::ostream& os, const CcnxFace &face);