add script setup() and thread methods

scripts/setup.lua

@@ -0,0 +1,38 @@
+-- example script that demonstrates use of setup() to pass
+-- data to and from the threads
+
+local counter = 1
+local threads = {}
+
+function setup(thread)
+   thread:set("id", counter)
+   table.insert(threads, thread)
+   counter = counter + 1
+end
+
+function init(args)
+   requests  = 0
+   responses = 0
+
+   local msg = "thread %d created"
+   print(msg:format(id))
+end
+
+function request()
+   requests = requests + 1
+   return wrk.request()
+end
+
+function response(status, headers, body)
+   responses = responses + 1
+end
+
+function done(summary, latency, requests)
+   for index, thread in ipairs(threads) do
+      local id        = thread:get("id")
+      local requests  = thread:get("requests")
+      local responses = thread:get("responses")
+      local msg = "thread %d made %d requests and got %d responses"
+      print(msg:format(id, requests, responses))
+   end
+end