This commit has some improvements for the code related to the OpenFlow 1.2
The changes are:

    - On match unpack, insert the proper match tlv object. (e.g, if the oxm field is
an inport, insert and inport object).
    - Add a compare method to oxm_tlvs and match_list, because there was not how to test
if the match in messages like flow_stats or flow_removed were correctly sent by the switch.
    - Improvements to the print format of oxm_tlvs.

Also, there is a minor fix for the groups test.
diff --git a/tests-1.2/groups.py b/tests-1.2/groups.py
index 4e936d0..76948db 100644
--- a/tests-1.2/groups.py
+++ b/tests-1.2/groups.py
@@ -161,7 +161,7 @@
 
 
     def send_data(self, packet, in_port):
-        self.logger.debug("Send packet on port " + str(in_port))
+        logging.debug("Send packet on port " + str(in_port))
         self.dataplane.send(in_port, str(packet))