Log Message:
Update to 1.17:

1.17  Wed May  3 16:52:03 EDT 2006
        - new_from_tree() uses a better rasterizer now, properly
          handling even more tortuous span issues. Thanks to Roland
          Schar.
        - Fixed as_XML rendering Thanks to Roger Crew.

1.16  Sat Feb 25 12:41:57 EST 2006
        - Fixed new_from_tree() to handle (ignore) tbody, thead and
          tfoot tags. Otherwise rows were ignored.

1.15  Fri Feb 24 15:34:13 EST 2006
        - Fixed some scoping issues ('my' collisions)
        - Fixed some undef issues running under -w (thanks to Carl
          Franks)