Merge pull request #2345 from embray/issue-2345

Remove platform.architecture() in FITS _array_to_file to improve speed on Mac
Conflicts:

	CHANGES.rst

git-svn-id: http://svn6.assembla.com/svn/pyfits/trunk@2677 ed100bfc-0583-0410-97f2-c26b58777a21