Feature Proposal : Make All Python Extensions User Configuration Independent (#1435)

* Updated all Python extension packages to use 'setup_py' on install.

* Fixed a few minor style issues with the updated Python packages.

var/spack/repos/builtin/packages/py-cffi/package.py

@@ -49,4 +49,4 @@ def install(self, spec, prefix):
         # building the shared library.
         os.environ['LDSHARED'] = "{0} -shared -pthread".format(spack_cc)
 
-        python('setup.py', 'install', '--prefix=%s' % prefix)
+        setup_py('install', '--prefix=%s' % prefix)