Added simple link manager implementation.
Added link admin stuff; unit tests to come.
diff --git a/net/api/src/main/java/org/onlab/onos/net/Link.java b/net/api/src/main/java/org/onlab/onos/net/Link.java
index e0f46b5..0f4275e 100644
--- a/net/api/src/main/java/org/onlab/onos/net/Link.java
+++ b/net/api/src/main/java/org/onlab/onos/net/Link.java
@@ -37,6 +37,13 @@
      */
     ConnectPoint dst();
 
+    /**
+     * Returns the link type.
+     *
+     * @return link type
+     */
+    Type type();
+
     // LinkInfo info(); // Additional link information / decorations
 
 }