[XML-SIG] xml.xpath and xml.xslt are available

[Martin v. Loewis]

I've added two packages to the XML package, xml.xpath and
xml.xslt. These are heavily based on 4XPath 4XSLT, but use PyXPath as
the expression parser. In theory, it should be possible to plug them
into a 4Suite installation, or use them stand-alone (without 4Suite).

In practice, much of the test suite passes, but there are still some
issues left. On the plus side, this has the chance of fixing the 4XSLT
bugs related to character sets, as the packages fully support Unicode.

To get an overview what has been taking literally from 4Suite and what
has been adopted, please have a look at xml/xpath/README.4XPath. Over
the next few months, we will strive to reduce the dependency on a
particular parser, and on Ft.Lib, so that really most of the files
become the same eventually.

If you find any problems, please let me know.

Regards,
Martin