Merge branch '3.2-stable' into astropy

Incorporates up through aa78ac3ad54441cf247e8f32ef32dd685a05c6fc

Conflicts:
	.authors
	docs/source/conf.py
	lib/pyfits/_release.py
	setup.cfg

Conflicts:

	.authors
	astropy/io/fits/card.py
	astropy/io/fits/fitsrec.py
	astropy/io/fits/hdu/table.py
	astropy/io/fits/header.py
	astropy/io/fits/tests/test_checksum.py
	astropy/io/fits/tests/test_core.py
	astropy/io/fits/tests/test_table.py
Added a changelog entry--not copying all the changes just mentioning that they were ported.
izip_longest is called zip_longest in Python 3
Fixed a couple small issues that only came up on Python 3. The one in hdulist affected all Python versions, however, in that HDUList.writeto did not immediately close the output file when done in the common case of the file being provided as a filename
Merge pull request #2368 from embray/fits-merge

Merge branch '3.2-stable' into astropy