Added notion of a general Store abstraction and wired it up in ClusterStore.
diff --git a/core/store/src/main/java/org/onlab/onos/store/impl/OptionalCacheLoader.java b/core/store/src/main/java/org/onlab/onos/store/impl/OptionalCacheLoader.java
index 47a42ee..dddd128 100644
--- a/core/store/src/main/java/org/onlab/onos/store/impl/OptionalCacheLoader.java
+++ b/core/store/src/main/java/org/onlab/onos/store/impl/OptionalCacheLoader.java
@@ -2,7 +2,7 @@
 
 import static com.google.common.base.Preconditions.checkNotNull;
 
-import org.onlab.onos.store.StoreService;
+import org.onlab.onos.store.common.StoreService;
 
 import com.google.common.base.Optional;
 import com.google.common.cache.CacheLoader;