I originally started working on updating patch 992750,
but decided after a short while to just start from
scratch, so I'm posting it as a new patch.  Sorry if
this isn't appropriate.

This patch provides a new open() method on ZipFile;
this method returns a file-like object for the
requested item in the archive.  This file-like object
only provides a read() method.

ZipFile.read was modified to use the new open method
(this was suggested by loewis in reference to patch
992750).

The patched zipfile.py passed the existing tests in the
test_zipfile.py from CVS.  New tests were added to
verify the operation of the object returned by open().
These tests were modeled after existing tests for
ZipFile.read(); two read fixed-size chunks from the
file-like object, and two others read random-sized chunks.

I have only run the tests on Windows XP, using
Python2.4 from the official Windows installer.  I will
test the patch out on Linux over the weekend.

If the patch is accepted I'll also generate and submit
patches for the appropriate documentation as well.