Adding DeviceAdminService facade and tests for SimpleDeviceManager.
diff --git a/net/api/src/main/java/org/onlab/onos/net/device/DeviceEvent.java b/net/api/src/main/java/org/onlab/onos/net/device/DeviceEvent.java
index 250e140..984f575 100644
--- a/net/api/src/main/java/org/onlab/onos/net/device/DeviceEvent.java
+++ b/net/api/src/main/java/org/onlab/onos/net/device/DeviceEvent.java
@@ -18,6 +18,12 @@
         DEVICE_ADDED,
 
         /**
+         * Signifies that some device attributes have changed; excludes
+         * availability changes.
+         */
+        DEVICE_UPDATED,
+
+        /**
          * Signifies that a device has been removed.
          */
         DEVICE_REMOVED,