Use setuptools, with fallback to distutils

This will allow `setup.py bdist_wheel` when setuptools is available.

Author: cmcqueen

setup.py

@@ -2,8 +2,11 @@
 
 import sys
 
-from distutils.core import setup
-from distutils.extension import Extension
+try:
+    from setuptools import setup, Extension
+except ImportError:
+    from distutils.core import setup
+    from distutils.extension import Extension
 
 import _version