Merge commit '44d4c3b9dcceca272e60cac8ba41f213965c4087' into astropy

Conflicts:
	setup.cfg
	setup.py
	tox.ini
Assigning inf and nan as header values simply shouldn't be allowed for now, as this is undefined by the FITS standard (and the previous behavior was nonsensical anyways).  Later this will be allowed optionally.

git-svn-id: http://svn6.assembla.com/svn/pyfits/trunk@2192 ed100bfc-0583-0410-97f2-c26b58777a21
Added changelog entries for spacetelescope/PyFITS#11

git-svn-id: http://svn6.assembla.com/svn/pyfits/trunk@2195 ed100bfc-0583-0410-97f2-c26b58777a21