Log Message:
Update py-flask-frozen to 0.12.

Version 0.12
~~~~~~~~~~~~

Released on 2015-10-05.

* Fix `#38 <https://github.com/SimonSapin/Frozen-Flask/issues/38>`_:
  add ``FREEZER_STATIC_IGNORE`` config option.
* Add ``FREEZER_IGNORE_404_NOT_FOUND`` config option.