[XeTeX] xetex, pstricks, dvipdfmx-unsafe.cfg

[Karl Berry]

FYI to all: we have changed dvipdfmx.cfg (in the pretest) so that
Ghostscript is always invoked safely. The primary practical implication
of this is that if you want to use xetex with pstricks,
1) be very sure that you trust all the input files, and
2) run
     xelatex -output-driver="xdvipdfmx -i dvipdfmx-unsafe.cfg -q -E" ....

The new dvipdfmx-unsafe.cfg simply reinstates the unsafe invocation of
gs (-dNOSAFER for those familiar with it).

This change will be active (in the pretest) after tonight's update. Only
the cfg files are changed, the (x)dvipdfmx binary was not affected.

We hope this can be made more convenient in the future, while still
saying safe. --good luck, karl.