added default host constructs to API

Change-Id: I3ef3e08559c7c4d73d8e4aee693589ee0830ed85
diff --git a/core/api/src/main/java/org/onlab/onos/net/Host.java b/core/api/src/main/java/org/onlab/onos/net/Host.java
index d66566d..667bb88 100644
--- a/core/api/src/main/java/org/onlab/onos/net/Host.java
+++ b/core/api/src/main/java/org/onlab/onos/net/Host.java
@@ -25,6 +25,13 @@
     MACAddress mac();
 
     /**
+     * Returns the VLAN ID tied to this host.
+     *
+     * @return VLAN ID value
+     */
+    short vlan();
+
+    /**
      * Returns set of IP addresses currently bound to the host MAC address.
      *
      * @return set of IP addresses; empty if no IP address is bound