[tldoc] TL13 documentation updates

[Karl Berry]

Hello TeX Live doc folk -- for those who don't already know, just wanted
to mention that we've started the pretest for this year's release
(http://tug.org/texlive/pretest.html).  I haven't made any updates to
the manual yet, but that is my next priority.  I hope I'll be able to
turn over something reasonably stable for translation by the end of the
week.

Meanwhile, the GUI doc strings have changed a little since last year,
I think.  See http://tug.org/doc.html#install-tl-xlate (the end of the
page) for info if you're not already familiar.

Thanks,
karl