py-weasyprint: update to 0.41.

Version 0.41
------------

Released on 2017-10-05.

WeasyPrint now depends on pdfrw >= 0.4.

New features:

* `#471 <https://github.com/Kozea/WeasyPrint/issues/471>`_:
  Support page marks and bleed.

Bug fixes:

* `#513 <https://github.com/Kozea/WeasyPrint/issues/513>`_:
  Don't crash on unsupported image-resolution values.
* `#506 <https://github.com/Kozea/WeasyPrint/issues/506>`_:
  Fix @font-face use with write_* methods.
* `#500 <https://github.com/Kozea/WeasyPrint/pull/500>`_:
  Improve readability of _select_source function.
* `#498 <https://github.com/Kozea/WeasyPrint/issues/498>`_:
  Use CSS prefixes as recommanded by the CSSWG.
* `#441 <https://github.com/Kozea/WeasyPrint/issues/441>`_:
  Fix rendering problems and crashes when using @font-face.
* `bb3a4db <https://github.com/Kozea/WeasyPrint/commit/bb3a4db>`_:
  Try to break pages after a block before trying to break inside it.
* `1d1654c <https://github.com/Kozea/WeasyPrint/commit/1d1654c>`_:
  Fix and test corner cases about named pages.

Documentation:

* `#508 <https://github.com/Kozea/WeasyPrint/pull/508>`_:
  Add missing libpangocairo dependency for Debian and Ubuntu.
* `a7b17fb <https://github.com/Kozea/WeasyPrint/commit/a7b17fb>`_:
  Add documentation on logged rendering steps.

(kleink)