cmake improve git submodule dependencies

Tools/tag_to_version.py

@@ -1,21 +0,0 @@
-#!/usr/bin/env python
-
-import subprocess
-import os
-import argparse
-
-p = argparse.ArgumentParser('finds major minor patch version from git tag')
-p.add_argument('--root', help="root of git repo", default=".")
-args = p.parse_args()
-os.chdir(args.root)
-p= subprocess.Popen(
-    'git describe --always --tags'.split(),
-    stdout=subprocess.PIPE, stderr=subprocess.PIPE)
-stdout, stderr = p.communicate()
-# Python3 needs this decode step.
-stdout = stdout.decode('ascii')
-res = stdout.split('-')[0].split('.')
-major = res[0].replace('v','')
-minor = res[1]
-patch = res[2]
-print("{:s}.{:s}.{:s}".format(major, minor, patch))