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.

from piecrust.formatting.base import Formatter


class TextileFormatter(Formatter):
    FORMAT_NAMES = ['textile', 'text']
    OUTPUT_FORMAT = 'html'

    def render(self, format_name, text):
        from textile import textile
        assert format_name in self.FORMAT_NAMES
        return textile(text)