Log Message:
Update py-weasyprint to 0.25.

Version 0.25
------------

Released on 2015-12-17.

New features:

* Support the 'q' unit.

Bug fixes:

* `#285: <https://github.com/Kozea/WeasyPrint/issues/285>`_:
  Fix a crash happening when splitting lines.
* `#284: <https://github.com/Kozea/WeasyPrint/issues/284>`_:
  Escape parenthesis in PDF links.
* `#280: <https://github.com/Kozea/WeasyPrint/pull/280>`_:
  Replace utf8 with utf-8 for gettext/django compatibility.
* `#269: <https://github.com/Kozea/WeasyPrint/pull/269>`_:
  Add support for use when frozen.
* `#250: <https://github.com/Kozea/WeasyPrint/issues/250>`_:
  Don't crash when attachments are not available.