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-mpmath/package.py

@@ -35,4 +35,4 @@ class PyMpmath(Package):
     extends('python')
 
     def install(self, spec, prefix):
-        python('setup.py', 'install', '--prefix=%s' % prefix)
+        setup_py('install', '--prefix=%s' % prefix)