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/flow/FlowRuleStore.java b/core/api/src/main/java/org/onlab/onos/net/flow/FlowRuleStore.java
index 0698721..f00b595 100644
--- a/core/api/src/main/java/org/onlab/onos/net/flow/FlowRuleStore.java
+++ b/core/api/src/main/java/org/onlab/onos/net/flow/FlowRuleStore.java
@@ -3,7 +3,7 @@
 import org.onlab.onos.net.DeviceId;
 
 /**
- * Manages inventory of flow rules.
+ * Manages inventory of flow rules; not intended for direct use.
  */
 public interface FlowRuleStore {