Add script to update KWSys from upstream

Utilities/Scripts/update-kwsys.bash

@@ -0,0 +1,22 @@
+#!/usr/bin/env bash
+
+set -e
+set -x
+shopt -s dotglob
+
+readonly name="KWSys"
+readonly ownership="KWSys Upstream <kwrobot@kitware.com>"
+readonly subtree="Source/kwsys"
+readonly repo="http://public.kitware.com/KWSys.git"
+readonly tag="master"
+readonly shortlog=true
+readonly paths="
+"
+
+extract_source () {
+    git_archive
+}
+
+export HOOKS_ALLOW_KWSYS=1
+
+. "${BASH_SOURCE%/*}/update-third-party.bash"