Support Kryo serialization for intent related types

- Implement the protected constructors
- Register the types in KryoFactory

Change-Id: I14214ed1703a8e4b3145625732c74600fc0aba06
diff --git a/src/main/java/net/onrc/onos/api/newintent/AbstractIntent.java b/src/main/java/net/onrc/onos/api/newintent/AbstractIntent.java
index f2e3d8a..0058860 100644
--- a/src/main/java/net/onrc/onos/api/newintent/AbstractIntent.java
+++ b/src/main/java/net/onrc/onos/api/newintent/AbstractIntent.java
@@ -16,6 +16,13 @@
         this.id = id;
     }
 
+    /**
+     * Constructor for serializer.
+     */
+    protected AbstractIntent() {
+        this.id = null;
+    }
+
     @Override
     public IntentId getId() {
         return id;