Add support for deleting or clearing all flows:
web/delete_flow.py all
web/clear_flow.py all
diff --git a/src/main/java/net/floodlightcontroller/flowcache/IFlowService.java b/src/main/java/net/floodlightcontroller/flowcache/IFlowService.java
index a534410..5e0db35 100644
--- a/src/main/java/net/floodlightcontroller/flowcache/IFlowService.java
+++ b/src/main/java/net/floodlightcontroller/flowcache/IFlowService.java
@@ -29,6 +29,13 @@
 		    String dataPathSummaryStr);
 
     /**
+     * Delete all previously added flows.
+     *
+     * @return true on success, otherwise false.
+     */
+    boolean deleteAllFlows();
+
+    /**
      * Delete a previously added flow.
      *
      * @param flowId the Flow ID of the flow to delete.
@@ -37,6 +44,13 @@
     boolean deleteFlow(FlowId flowId);
 
     /**
+     * Clear the state for all previously added flows.
+     *
+     * @return true on success, otherwise false.
+     */
+    boolean clearAllFlows();
+
+    /**
      * Clear the state for a previously added flow.
      *
      * @param flowId the Flow ID of the flow to clear.