Use README.rst as 'long_description' for 'setup()'.

Fixes #440.

setup.py

@@ -1,14 +1,14 @@
-import sys
+import os
 
 
-try:
-    from setuptools import setup, find_packages
-except ImportError:
-    from distutils.core import setup, find_packages
+from setuptools import setup
+from setuptools import find_packages
 
+here = os.path.abspath(os.path.dirname(__file__))
 
-if sys.version_info <= (2, 5):
-    raise Exception('Requires Python Version 2.6 or above... exiting.')
+
+with open(os.path.join(here, 'README.rst')) as f:
+    README = f.read()
 
 
 REQUIREMENTS = [
@@ -27,6 +27,7 @@
     description='API Client library for Google Cloud',
     author='JJ Geewax',
     author_email='jj@geewax.org',
+    long_description=README,
     scripts=[],
     url='https://github.com/GoogleCloudPlatform/gcloud-python',
     packages=find_packages(),