Add backend support for collecting the time it takes to
install each Flow.

The new REST call is "wm/flow/measurement-get-per-flow-install-time/json"
The result is returned in a multi-line string with the following format
per line:

  ThreadAndTimePerFlow <ThreadId> <TotalThreads> <Time(ns)>
diff --git a/src/main/java/net/floodlightcontroller/flowcache/web/FlowWebRoutable.java b/src/main/java/net/floodlightcontroller/flowcache/web/FlowWebRoutable.java
index 9fa5e63..fd9a319 100644
--- a/src/main/java/net/floodlightcontroller/flowcache/web/FlowWebRoutable.java
+++ b/src/main/java/net/floodlightcontroller/flowcache/web/FlowWebRoutable.java
@@ -25,6 +25,7 @@
         router.attach("/measurement-store-path/json", MeasurementStorePathFlowResource.class);
         router.attach("/measurement-install-paths/{num-threads}/json", MeasurementInstallPathsFlowResource.class);
         router.attach("/measurement-get-install-paths-time-nsec/json", MeasurementGetInstallPathsTimeNsecFlowResource.class);
+        router.attach("/measurement-get-per-flow-install-time/json", MeasurementGetPerFlowInstallTimeFlowResource.class);
         router.attach("/measurement-clear-all-paths/json", MeasurementClearAllPathsFlowResource.class);
         return router;
     }