Fix a Python 3 incompatibility that was introduced by the fix for #48 (which was written before the switchover to unified codebase)

git-svn-id: http://svn6.assembla.com/svn/pyfits/branches/3.2-stable@2541 ed100bfc-0583-0410-97f2-c26b58777a21
Oops; jumped the gun a bit on that last commit.  That wasn't an issue in the 3.2-stable branch, which still relies on 2to3

git-svn-id: http://svn6.assembla.com/svn/pyfits/branches/3.2-stable@2543 ed100bfc-0583-0410-97f2-c26b58777a21
Squashed commit of the following:

commit 17fbac04ad978126d771f4c37529a2ccb89f676a
Author: Erik M. Bray <embray@stsci.edu>
Date:   Sat Feb 1 14:10:38 2014 -0500

    A changelog entry for the first fix for #37

commit b70a24de89fad2487ade6e854162f004726cdb75
Author: Erik M. Bray <embray@stsci.edu>
Date:   Sat Feb 1 14:09:04 2014 -0500

    Fix the first issue related to spacetelescope/PyFITS#37, that Python 2 was allowing non-ASCII strs to be assigned as Header values

Conflicts:

	lib/pyfits/card.py
	lib/pyfits/tests/test_header.py

git-svn-id: http://svn6.assembla.com/svn/pyfits/branches/3.2-stable@2544 ed100bfc-0583-0410-97f2-c26b58777a21