fix setup.py for newer cython/distutil versions

setup.py

@@ -1,39 +1,34 @@
 import os
-from setuptools import setup
+from distutils.core import setup
 from distutils.extension import Extension
+from Cython.Distutils import build_ext
 
-import sys
-if 'setuptools.extension' in sys.modules:
-    m = sys.modules['setuptools.extension']
-    m.Extension.__dict__ = m._Extension.__dict__
 
 def read(fname):
     return open(os.path.join(os.path.dirname(__file__), fname)).read()
 
 
-CYTHON_SOURCES =  """src/p2t.pyx""".split("\n")
-
+CYTHON_SOURCES = """src/p2t.pyx""".split("\n")
 CPP_SOURCES = """poly2tri/common/shapes.cc
 poly2tri/sweep/advancing_front.cc
 poly2tri/sweep/cdt.cc
 poly2tri/sweep/sweep.cc
 poly2tri/sweep/sweep_context.cc""".split("\n")
 
+
 mod_math = Extension(
     "p2t",
     CYTHON_SOURCES + CPP_SOURCES,
-    language = "c++"
+    language="c++"
 )
 
 setup(
-    name = "poly2tri",
-    version = "0.3.3",
-    author = "Mason Green",
-    description = "A 2D constrained Delaunay triangulation library",
-    long_description = read('README'),
-    url = "http://code.google.com/p/poly2tri/",
-
-    ext_modules = [mod_math],
-    setup_requires = ["cython==0.14.1", "setuptools_cython==0.2.1"],
-    install_requires = ["cython==0.14.1"],
+    name="poly2tri",
+    version="0.3.3",
+    author="Mason Green",
+    description="A 2D constrained Delaunay triangulation library",
+    long_description=read('README'),
+    url="http://code.google.com/p/poly2tri/",
+    ext_modules=[mod_math],
+    cmdclass={'build_ext': build_ext},
 )