utils: Extending l2-rate-tracer to include raw packet counts

This is similar to the existing ndn-l3-rate-tracer
diff --git a/utils/tracers/l2-rate-tracer.cc b/utils/tracers/l2-rate-tracer.cc
index 823977b..cf4af72 100644
--- a/utils/tracers/l2-rate-tracer.cc
+++ b/utils/tracers/l2-rate-tracer.cc
@@ -109,7 +109,9 @@
 
      << "Type" << "\t"
      << "Packets" << "\t"
-     << "Kilobytes";
+     << "Kilobytes" << "\t"
+     << "PacketsRaw" << "\t"
+     << "KilobytesRaw";
 }
 
 void
@@ -133,7 +135,9 @@
  << interface << "\t"                                                  \
  << printName << "\t"                                                   \
  << STATS(2).fieldName  << "\t"                                         \
- << STATS(3).fieldName << "\n";
+ << STATS(3).fieldName << "\t"                                         \
+ << STATS(0).fieldName << "\t"                                         \
+ << STATS(1).fieldName / 1024.0 << "\n";
 
 void
 L2RateTracer::Print (std::ostream &os) const