2to3: Use absolute imports.

The new import `absolute_import` is added the `from __future__ import`
statement and The 2to3 `import` fixer is run to make the imports
compatible. There are several things that need to be dealt with to make
this work.

1) Files meant to be run as scripts run in a different environment than
files imported as part of a package, and so changes to those files need
to be skipped. The affected script files are:

    * all setup.py files
    * numpy/core/code_generators/generate_umath.py
    * numpy/core/code_generators/generate_numpy_api.py
    * numpy/core/code_generators/generate_ufunc_api.py

2) Some imported modules are not available as they are created during
the build process and consequently 2to3 is unable to handle them
correctly. Files that import those modules need a bit of extra work.
The affected files are:

    * core/__init__.py,
    * core/numeric.py,
    * core/_internal.py,
    * core/arrayprint.py,
    * core/fromnumeric.py,
    * numpy/__init__.py,
    * lib/npyio.py,
    * lib/function_base.py,
    * fft/fftpack.py,
    * random/__init__.py

Closes #3172

Author: charris

numpydoc/comment_eater.py

@@ -1,4 +1,4 @@
-from __future__ import division
+from __future__ import division, absolute_import
 
 import sys
 if sys.version_info[0] >= 3:

numpydoc/compiler_unparse.py

@@ -10,7 +10,7 @@
     fixme: We may want to move to using _ast trees because the compiler for
            them is about 6 times faster than compiler.compile.
 """
-from __future__ import division
+from __future__ import division, absolute_import
 
 import sys
 from compiler.ast import Const, Name, Tuple, Div, Mul, Sub, Add

numpydoc/docscrape.py

@@ -1,7 +1,7 @@
 """Extract reference documentation from the NumPy source tree.
 
 """
-from __future__ import division
+from __future__ import division, absolute_import
 
 import sys
 import inspect

numpydoc/docscrape_sphinx.py

@@ -1,4 +1,4 @@
-from __future__ import division
+from __future__ import division, absolute_import
 
 import re, inspect, textwrap, pydoc
 import sphinx

numpydoc/linkcode.py

@@ -9,7 +9,7 @@
     :license: BSD, see LICENSE for details.
 
 """
-from __future__ import division
+from __future__ import division, absolute_import
 
 import warnings
 import collections

numpydoc/numpydoc.py

@@ -15,7 +15,7 @@
 .. [1] https://github.com/numpy/numpy/blob/master/doc/HOWTO_DOCUMENT.rst.txt
 
 """
-from __future__ import division
+from __future__ import division, absolute_import
 
 import sphinx
 import collections

numpydoc/phantom_import.py

@@ -14,7 +14,7 @@
 .. [1] http://code.google.com/p/pydocweb
 
 """
-from __future__ import division
+from __future__ import division, absolute_import
 
 import imp, sys, compiler, types, os, inspect, re
 

numpydoc/plot_directive.py

@@ -74,7 +74,7 @@
   to make them appear side-by-side, or in floats.
 
 """
-from __future__ import division
+from __future__ import division, absolute_import
 
 import sys, os, glob, shutil, imp, warnings, re, textwrap, traceback
 import sphinx

numpydoc/tests/test_docscrape.py

@@ -1,5 +1,5 @@
 # -*- encoding:utf-8 -*-
-from __future__ import division
+from __future__ import division, absolute_import
 
 import sys, textwrap
 

numpydoc/traitsdoc.py

@@ -13,7 +13,7 @@
 .. [2] http://code.enthought.com/projects/traits/
 
 """
-from __future__ import division
+from __future__ import division, absolute_import
 
 import inspect
 import os