Renamed *Instance to *Node for better readability and to avoid conflict with notion of Karaf instance.
Added cluster service and trivial store implementations.
diff --git a/core/api/src/main/java/org/onlab/onos/net/device/DeviceStore.java b/core/api/src/main/java/org/onlab/onos/net/device/DeviceStore.java
index 851fbc1..3ed477b 100644
--- a/core/api/src/main/java/org/onlab/onos/net/device/DeviceStore.java
+++ b/core/api/src/main/java/org/onlab/onos/net/device/DeviceStore.java
@@ -10,7 +10,7 @@
 import java.util.List;
 
 /**
- * Manages inventory of infrastructure devices.
+ * Manages inventory of infrastructure devices; not intended for direct use.
  */
 public interface DeviceStore {