Added notion of a general Store abstraction and wired it up in ClusterStore.
diff --git a/core/api/src/main/java/org/onlab/onos/cluster/ClusterStoreDelegate.java b/core/api/src/main/java/org/onlab/onos/cluster/ClusterStoreDelegate.java
new file mode 100644
index 0000000..b247c27
--- /dev/null
+++ b/core/api/src/main/java/org/onlab/onos/cluster/ClusterStoreDelegate.java
@@ -0,0 +1,9 @@
+package org.onlab.onos.cluster;
+
+import org.onlab.onos.store.StoreDelegate;
+
+/**
+ * Cluster store delegate abstraction.
+ */
+public interface ClusterStoreDelegate extends StoreDelegate<ClusterEvent> {
+}