run iterations of msbuild and record avg time

gistfile1.py

#!/usr/bin/env python

from datetime import datetime
import subprocess

starttime = datetime.now()
print "start time:", starttime

numIterations = 1

for i in xrange(0,numIterations):
	print "build num:", i
	subprocess.check_call([r"C:\windows\Microsoft.NET\Framework\v4.0.30319\msbuild.exe", r"C:\Users\matt.jackson\projects\v3\BuildAllSolutions.msbuild", "/t:CleanBuildDir;BuildCommonIntegrationMessages,BuildPayments"])
	print "build finished:", datetime.now()

endtime = datetime.now()
print "start time:", starttime
print "endtime:", endtime
print "duration:", endtime - starttime
print "avg:", (endtime - starttime) / numIterations