Intermediate transport support

Changes:
- Adds a procedure to fill the pipeline in different use cases;
- Adds a new utility function to fill the MPLS flow tables;
- Adds an utility function to print the ports stats

Change-Id: I8928b177ac93e4c05ced4573be87c1c9361d35b5
diff --git a/src/python/loxi/of13/oxm.py b/src/python/loxi/of13/oxm.py
index 193ff6f..9b46aab 100755
--- a/src/python/loxi/of13/oxm.py
+++ b/src/python/loxi/of13/oxm.py
@@ -6152,6 +6152,7 @@
 
 VPWS                        = 1
 TUNNEL_ID_BASE              = 0x10000
+L3_PHP                      = 32
 
 class exp1ByteValue(oxm):
     type_len = 0xffff0005