Test about using cython

gensetup.py

@@ -49,10 +49,14 @@ def load_version():
 if argv[1] == '--setup.py':
     with open('setup.py', 'wt') as f:
         print(
-f'''#!/usr/bin/python3
+f'''#!/usr/bin/env python3
 # This file is auto generated. Do not modify
 from setuptools import setup
+
+from Cython.Build import cythonize
+
 setup(
+    ext_modules = cythonize(["typedload/dataloader.py", "typedload/typechecks.py",  "typedload/exceptions.py"]),
     name='typedload',
     version={load_version()!r},
     description='{DESCRIPTION}',