[ONOS-5821] (core) Develop Virtual Event Delivery Service

Chagnes
1. Virtual event is added
2. Virtual event listener manager is added
3. Virtual listener registry manager is added
4. test cases are added

Change-Id: I4157ab299c8316595eecafc8328e99433399a80c
diff --git a/incubator/api/src/main/java/org/onosproject/incubator/net/virtual/event/package-info.java b/incubator/api/src/main/java/org/onosproject/incubator/net/virtual/event/package-info.java
new file mode 100644
index 0000000..5032dc3
--- /dev/null
+++ b/incubator/api/src/main/java/org/onosproject/incubator/net/virtual/event/package-info.java
@@ -0,0 +1,20 @@
+/*
+ * Copyright 2017-present Open Networking Laboratory
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * Virtual network event delivery subsystem interfaces & supporting abstractions.
+ */
+package org.onosproject.incubator.net.virtual.event;