[tex-live] PDF 1.5 by default in TL 2010

[Karl Berry]

(Sorry for the cross-posting.)

For TL 2010, we would like to change the default PDF output version to
PDF 1.5 (proposed by Elie Roux).  This is so we can use
\pdfcompresslevel and generate noticeably smaller PDF's by default.

The executables etex, pdftex, pdflatex, luatex, and lualatex would be
affected (among other more obscure ones).  Of course it's irrelevant to "tex".
ConTeXt has been using 1.5 for some time.

We've done a fair amount of research and can't find any significant and
reasonably current software that doesn't support 1.5.  For instance,
Acrobat5 does not read it, but Acrobat6 does.  PDFBox-0.7.3.jar (3 years
old) doesn't read it, but 0.8 (>1 year) does.

>From Taco, we know that the iLiad e-reader and others do not support
1.5, but they have such specialized needs anyway that this does not seem
like a stopper.

If anyone knows of other reasons not to make the change, please speak up.

This'll be mentioned again, but I thought to bring it up early, too.

Thanks,
Karl