Added a simple device manager to have a working provider broker.
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 62fc9f8..200f682 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
@@ -18,8 +18,9 @@
/**
* Signifies that this link is potentially comprised from multiple
- * underlying segments or hops, e.g. optical links, tunnel links,
- * multi-hop links spanning 'dark' switches
+ * underlying segments or hops, and as such should be used to tag
+ * links traversing optical paths, tunnels or intervening 'dark'
+ * switches.
*/
INDIRECT
}