Converts from Microsoft's XPS format to PDF.
This uses the Ghostscript program ghostpdl to
do the conversion.

How it works
============
 $ ruby xps2pdf.rb [... XPS files]

It'll download ghostpdl program, compile it &
convert all the XPS input files. Output it
written to FILE.pdf (input is FILE.xps).

Tested on Mac OS X 10.6.7.
Require Ruby 1.9.2.