hack comix for windows use gbk as filename code

    Comix is a python application to view comic. it use pygtk as GUI library, so technically, it can be used under windows. But unfortunately, it has code problem under windows. OK, 2 fix it, open src/filechooser.py:214.

            gbkpath = paths[0].decode('utf-8').encode('gbk')

            self._window.file_handler.open_file(gbkpath)

    done.