DOC: Make documentation of nansum current with 1.9.

Simply state that Numpy versions < 1.9 returned nan instead of zero
for the sum of empty slices.
BUG: use correct type for hash values

As of Python 3.2 hash values are of type Py_hash_t. Previous versions use C long.
Merge pull request #3747 from cgohlke/py_hash_t

Fix issue #3743: Hash changed signature in Python 3.3
Merge pull request #3746 from charris/fix-nansum-documentation

DOC: Make documentation of nansum current with 1.9.
DOC: improve __numpy_ufunc__ documentation

Cross-reference it from Ufunc documentation and mention the version it
was added.
Fixes in the npyio documentation

Fixes the "see also" section of savetxt, which
described savez as compressing (closes #587 ). Also
replaces all occurences of .npy and .npz to use double backticks.
Some had, some did not, and some had " symbols.
small typo
MAINT: changed 'closest' interpolation to 'nearest'
TST: note on overwrite_input parameter in percentile

* added note that `overwrite_input` has not effect when `a` is not
  an array in the percentile function.
* added unit test to verify that no error is raised when `a` is not
  an array and `overwrite_input` is True.
Merge pull request #3482 from jjhelmus/linspace_enh

ENH: Add dtype parameter to linspace and logspace functions.
MAINT: update release scripts for building OS X binaries.

Works with Python 3.x now that bdist_mpkg is ported (thanks @matthew-brett).
BUG: fix #3017 Inconsistency in indexing 0-d arrays with Ellipsis.
BUG: Fix issue with PR #3491

Don't convert unicode string to ascii string before getting byte length.
Also, get length of non string type as ascii or unicode depending on
output string type.
BLD: fix Bento build.

Issue was introduced with PR-3524, the ufunc override stuff.
BLD: add new test extensions (rational, struct_ufunc, operand_flag) to Bento build.
Merge pull request #3765 from charris/forward-port-3761

BUG: Fix issue with PR #3491
TST: exercise median of median of 5 code by using a median of 3 killer dataset
ENH: remove an always true conditional

v[1] < v[2] is guaranteed by the swapping a few lines above
Merge pull request #3658 from jjhelmus/percentile_enh_new

ENH: percentile function with additional parameters and vectorization
Merge pull request #3752 from pv/doc-some-xref

DOC: improve __numpy_ufunc__ documentation