Revision 268394

Added a TraX liaison for the <style> task.  This enables Apache's Xalan2
and Sun's JAXP1.1 implementations to be used.

I don't expect many developers to have multiple XSLT implementations in
their classpath, but if they do, I made the TraX liaison the default
for several reasons:
  1) It is standard
  2) It is the most modern interface
  3) It is designed as an pluggable interface, so in theory (though perhaps
     down the road a bit), it should be the only liaison required.