MAINT: Remove unneeded version check from multiarray/common.c.

A version check for Python >= 2.6 is no longer needed as versions < 2.6
are no longer supported.
Merge pull request #3305 from arinkverma/master

MAINT: Remove unneeded version check from multiarray/common.c.
Fix potential reference leak
Merge pull request #3303 from ContinuumIO/rational_fix

Fix clang build issue
BLD: fix Bento build after umath_linalg move from core to linalg module.
Merge pull request #3307 from rgommers/fix-bento-build

BLD: fix Bento build after umath_linalg move from core to linalg module.
Merge pull request #3289 from rkern/fix-numpy.org-links

BUG: Fix some README links to point to www.numpy.org
Merge pull request #3264 from endolith/patch-1

DOC: Change example to demonstrate function
Merge pull request #3182 from juliantaylor/debug-ext

get_shared_lib_extension(): strip debug extension from so ext
ENH: use intrinsics for isnan, isfinite and isinf

Use of intrinsics avoids expensive function calls in tight loops on x86
cpus where these operations are implemented in hardware while still
retaining same portability.
More than doubles performance of np.isnan/isinf/isfinite.
This change allows ufunc operand flags to be set in addition to the
default operand flags set by the nditer object. For example, after
calling PyUFunc_FromFuncAndData() to create a ufunc object, the first
operand can be set to be read/write like so:

ufunc->op_flags[0] = NPY_ITER_READWRITE

Setting flags for output operands is not supported at this time and
will raise an exception.

This change also allows the global nditer flags to be set, so after
setting the read/write flag, the reduce ok flag could be set like so:

ufunc->iter_flags = NPY_ITER_REDUCE_OK
minor fixes for previous ufunc operand flag change
initialize ufunc op_flags pointer in frompyfunc()
correctly initialize op_flags and iter_flags in frompyfunc()
Remove guard against read+write output operands
Update c api documentation
Add test for setting operand flags through c api
Fix python 2/3 issues in operand_flag_tests module
Fix formatting issues
STY: pep8 and pep257 audit.

Audit numpy/lib/arraypad.py for pep8 and pep257 compliance.
Also fix a few minor docstring corrections converting ] into ) or
vice versa.