some interface changes to flow and packet
diff --git a/core/api/src/main/java/org/onlab/onos/net/flow/TrafficTreatment.java b/core/api/src/main/java/org/onlab/onos/net/flow/TrafficTreatment.java
index 0eb5299..b8b9c10 100644
--- a/core/api/src/main/java/org/onlab/onos/net/flow/TrafficTreatment.java
+++ b/core/api/src/main/java/org/onlab/onos/net/flow/TrafficTreatment.java
@@ -25,7 +25,7 @@
          *
          * @param instruction new instruction
          */
-        void add(Instruction instruction);
+        Builder add(Instruction instruction);
 
         /**
          * Builds an immutable traffic treatment descriptor.