Fix a TODO item that is necessary for fileobj_is_binary to return the correct result for a StringIO object in Python 3

Conflicts:

	lib/pyfits/util.py

git-svn-id: http://svn6.assembla.com/svn/pyfits/trunk@2507 ed100bfc-0583-0410-97f2-c26b58777a21
Regression test and fix for https://trac.assembla.com/pyfits/ticket/217

git-svn-id: http://svn6.assembla.com/svn/pyfits/trunk@2508 ed100bfc-0583-0410-97f2-c26b58777a21
A couple fixups for Python 3 compatibility

git-svn-id: http://svn6.assembla.com/svn/pyfits/trunk@2509 ed100bfc-0583-0410-97f2-c26b58777a21