[tldoc] Script to check the links in the documentation

[Karl Berry]

    http://groups.google.com/group/comp.text.tex/topics

Works in a browser.  Am not inclined to change it to the current weird
resulting url, since that seems much more likely to change.  

    http://ctan.example.org/tex-archive/systems/texlive/tlnet/

An example, as stated :).

    http://mirror.ctan.org/tex-archive/fonts/greek/cb

Changing to .../cbfonts.

Thanks,
k