Remove unused imports

setup.py

-import importlib
-import sys
 from distutils.command.build import build
 from distutils.extension import Extension
-from subprocess import check_call, check_output
+from subprocess import check_output
 
 import numpy
 from Cython.Distutils import build_ext
 from setuptools import setup
-from setuptools.command.install import install
 
 extensions = [
     Extension(