publish: Make publisher more powerful and better exposed on the command line. * Make the `chef publish` command have one sub-command per publish target. * Add custom argument parsing per publisher to have strong extra arguments available per publish target. * Make publish targets a first class citizen of the `PieCrust` app class.

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