Adding support for VLAN_PUSH with EtherType (incl. Q-in-Q)

 - Allowing VLAN_PUSH Instruction to use ethernetType (incl. using REST API)
 - Adding QINQ (0x88a8) Ethernet type
 - Updating InstructionCodec decoders/encoders
 - Updating TrafficTreatment/FlowEntryBuilder

Change-Id: I723cc936a8a49c39da9abe65ba9e5b1bdc1392bf
diff --git a/core/api/src/main/java/org/onosproject/net/flow/TrafficTreatment.java b/core/api/src/main/java/org/onosproject/net/flow/TrafficTreatment.java
index d0de8e4..1ccceea 100644
--- a/core/api/src/main/java/org/onosproject/net/flow/TrafficTreatment.java
+++ b/core/api/src/main/java/org/onosproject/net/flow/TrafficTreatment.java
@@ -291,6 +291,13 @@
         Builder pushVlan();
 
         /**
+         * Pushes a new VLAN tag using the supplied Ethernet type.
+         *
+         * @return a treatment builder
+         */
+        Builder pushVlan(EthType ethType);
+
+        /**
          * Any instructions preceded by this method call will be deferred.
          * @return a treatment builder
          */