Fixes #208

Conflicts:

	CHANGES.txt
	lib/pyfits/tests/test_checksum.py
	lib/pyfits/tests/test_groups.py
	lib/pyfits/tests/test_hdulist.py
	lib/pyfits/tests/test_image.py

git-svn-id: http://svn6.assembla.com/svn/pyfits/branches/3.0-stable@2115 ed100bfc-0583-0410-97f2-c26b58777a21