Fixed a mistake in linalg.eig() documentation.
BUG: Use io.open instead of open for compatibility.

The recent Python 3 fix adding encoding="utf-8" to the open function
fails on Python 2 because the encoding keyword is not defined. The
solution is to use io.open, which is available for Python 2.6 and 2.7
and is an alias for open when Python >= 3.0. It is reputed to be slow
when running in 2.6, but that should not be a problem.
Merge pull request #3623 from charris/fix-postprocess-script

BUG: Use io.open instead of open for compatibility.
DOC: Update HOWTO_RELEASE.rst.txt.

The current version is out of date. Supported Python versions have
changed, the buildbot is no longer reachable, some links are dead,
etc.
Merge pull request #3625 from charris/update-howtorelease

DOC: Update HOWTO_RELEASE.rst.txt.
ENH: Make savetxt work with file like objects.

Accept any object with a "write" method as that is the only method
called by the code.
TST: Test that savetxt works with objects having a write method.
Merge pull request #3626 from charris/gh-3397

gh-3397
Merge pull request #2721 from abalkin/master

Mistake in linalg.eig() documentation
ENH: add PyDataMem_NEW_ZEROED which allocates memory with calloc
ENH: use PyDataMem_NEW_ZEROED for PyArray_Zeros

PyDataMem_NEW_ZEROED uses calloc which will take advantage of the fact
that most operating systems provide already zero initialized memory
blocks on larger allocations.
Additionally this memory can be sparse (= mapped to a single zero page)
on some systems (e.g. linux) reducing memory usage of applications
using sparse arrays.