CORD-176, CORD-431 Switch to new VTN API

- Implemented VTN store and manager to keep network states
- Implemented the new VTN API for service network and port

Change-Id: Id8f5d0e609fa3deba782ff2265fc0d3175cbcb4c
diff --git a/src/main/java/org/opencord/cordvtn/api/InstanceService.java b/src/main/java/org/opencord/cordvtn/api/InstanceService.java
index a8e0f77..add968f 100644
--- a/src/main/java/org/opencord/cordvtn/api/InstanceService.java
+++ b/src/main/java/org/opencord/cordvtn/api/InstanceService.java
@@ -25,7 +25,8 @@
 public interface InstanceService {
 
     /**
-     * Adds a service instance on a given connect point.
+     * Adds a service instance on a given connect point. Or updates if the
+     * instance already exists.
      *
      * @param connectPoint connect point of the instance
      */