Get the HTTP response code of any URL (with an optimal HEAD request); returns an Integer.
def getResponseCode = { String urlString ->
URL u = new URL(urlString)
HttpURLConnection huc = (HttpURLConnection) u.openConnection()
huc.setRequestMethod("HEAD")
huc.setRequestProperty("User-Agent", "Mozilla/5.0 (Windows; U; Windows NT 6.0; en-US; rv:1.9.1.2) Gecko/20090729 Firefox/3.5.2 (.NET CLR 3.5.30729)")
huc.connect()
//println huc.getResponseCode()
return huc.getResponseCode()
}