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/apps/ccnx-consumer-batches.cc b/apps/ccnx-consumer-batches.cc
index deb4a0d..da95d48 100644
--- a/apps/ccnx-consumer-batches.cc
+++ b/apps/ccnx-consumer-batches.cc
@@ -72,6 +72,7 @@
 {
   // std::cout << Simulator::Now () << " adding batch of " << amount << "\n";
   m_seqMax += amount;
+  m_rtt->ClearSent (); // this is important, otherwise RTT estimation for the new batch will be affected by previous batch history
   ScheduleNextPacket ();
 }