serve: Fix corner cases where the pipeline doesn't run correctly. * When `chef serve` is run before the `assets` folder is created, monitor that folder suddenly appearing and rebuild the pipeline. * Do the same when the `config.yml` file has changed.

import os


def slashfix(path):
    if path is None:
        return None
    if isinstance(path, str):
        return path.replace('/', os.sep)
    fixed = []
    for p in path:
        fixed.append(p.replace('/', os.sep))
    return fixed