Adding to the 'devices' cli command an output that displays the local connectivity of a device.
For example, "id=of:0000000000000203, available=true, local-status=connected 18m7s ago, role=STANDBY, ..."
Also increasing the resolution of the TimeAgo utility.

Change-Id: Ie1b89bd193552e0edd38a9ca28c5ce99b1d27c19
diff --git a/core/api/src/main/java/org/onosproject/net/device/DeviceService.java b/core/api/src/main/java/org/onosproject/net/device/DeviceService.java
index 290f7d7..1cb90e8 100644
--- a/core/api/src/main/java/org/onosproject/net/device/DeviceService.java
+++ b/core/api/src/main/java/org/onosproject/net/device/DeviceService.java
@@ -166,4 +166,14 @@
      */
     boolean isAvailable(DeviceId deviceId);
 
+    /**
+     * Indicates how long ago the device connected or disconnected from this
+     * controller instance.
+     *
+     * @param deviceId device identifier
+     * @return a human readable string indicating the time since the device
+     *          connected-to or disconnected-from this controller instance.
+     */
+    String localStatus(DeviceId deviceId);
+
 }