Adds support for using Microsoft's msxsl command-line
XSLT processor (see
us/dnxml/html/msxsl.asp) to xsl-process.el.
Note that I had to comment out the first "generic" entry
in xsl-process-error-regexps since it was interfering with
my new regexp, and I didn't feel comfortable messing
with the "generic" one since I don't know what it's trying
Also, fixed a documentation bug in the xsl-process
function while I was at it.