Add missing sphinxext files

doc/sphinxext/MANIFEST.in

+recursive-include tests *.py
+include *.txt

doc/sphinxext/README.txt

+=====================================
+numpydoc -- Numpy's Sphinx extensions
+=====================================
+
+Numpy's documentation uses several custom extensions to Sphinx.  These
+are shipped in this ``numpydoc`` package, in case you want to make use
+of them in third-party projects.
+
+The following extensions are available:
+
+  - ``numpydoc``: support for the Numpy docstring format in Sphinx, and add
+    the code description directives ``np:function``, ``np-c:function``, etc.
+    that support the Numpy docstring syntax.
+
+  - ``numpydoc.traitsdoc``: For gathering documentation about Traits attributes.
+
+  - ``numpydoc.plot_directive``: Adaptation of Matplotlib's ``plot::``
+    directive. Note that this implementation may still undergo severe
+    changes or eventually be deprecated.
+
+
+numpydoc
+========
+
+Numpydoc inserts a hook into Sphinx's autodoc that converts docstrings
+following the Numpy/Scipy format to a form palatable to Sphinx.
+
+Options
+-------
+
+The following options can be set in conf.py:
+
+- numpydoc_use_plots: bool
+
+  Whether to produce ``plot::`` directives for Examples sections that
+  contain ``import matplotlib``.
+
+- numpydoc_show_class_members: bool
+
+  Whether to show all members of a class in the Methods and Attributes
+  sections automatically.
+
+- numpydoc_edit_link: bool  (DEPRECATED -- edit your HTML template instead)
+
+  Whether to insert an edit link after docstrings.

doc/sphinxext/setup.py

+from distutils.core import setup
+import setuptools
+import sys, os
+
+version = "0.4"
+
+setup(
+    name="numpydoc",
+    packages=["numpydoc"],
+    package_dir={"numpydoc": ""},
+    version=version,
+    description="Sphinx extension to support docstrings in Numpy format",
+    # classifiers from http://pypi.python.org/pypi?%3Aaction=list_classifiers
+    classifiers=["Development Status :: 3 - Alpha",
+                 "Environment :: Plugins",
+                 "License :: OSI Approved :: BSD License",
+                 "Topic :: Documentation"],
+    keywords="sphinx numpy",
+    author="Pauli Virtanen and others",
+    author_email="pav@iki.fi",
+    url="http://github.com/numpy/numpy/tree/master/doc/sphinxext",
+    license="BSD",
+    zip_safe=False,
+    install_requires=["Sphinx >= 1.0.1"],
+    package_data={'numpydoc': 'tests', '': ''},
+    entry_points={
+        "console_scripts": [
+            "autosummary_generate = numpydoc.autosummary_generate:main",
+        ],
+    },
+)