[Python-3000] New io system and binary data

[skip at pobox.com]

    Charles> There's another place in the tutorial section
    Charles> http://docs.python.org/dev/3.0/tutorial/inputoutput.html and
    Charles> search for "On Windows and the Macintosh, 'b' appended to the
    Charles> mode opens the file in binary mode,"

I fixed that up as well.  I mentioned the automatic encode/decode for text
files there as well, though I'm not sure it needs to be mentioned in the
tutorial.

Skip