tests: Fix processing tests on Windows. See the comment in `pipeline.py` for more info but basically I was passing already initialized processors to the worker pool, which means pickling the whole app. Pretty bad. Interesting that it only broke on Windows, though.

#!/bin/sh

CUR_DIR="$( cd "$( dirname "$0" )" && pwd )"
CHEF=${CUR_DIR}/../bin/chef
OUT_DIR=${CUR_DIR}/../piecrust/resources/messages
ROOT_DIR=${CUR_DIR}/messages

$CHEF --root=$ROOT_DIR bake -o $OUT_DIR
rm ${OUT_DIR}/index.html