Add support for Sensu integration with StackLight

This patch deployes Sensu as a cluster and adds a StackLight client.
diff --git a/heka/aggregator/output/nagios.yml b/heka/aggregator/output/nagios.yml
new file mode 100644
index 0000000..cbf7654
--- /dev/null
+++ b/heka/aggregator/output/nagios.yml
@@ -0,0 +1,2 @@
+classes:
+- service.heka.aggregator.output.nagios