rename 'preamble' and 'postamble' options to 'header' and 'footer'
add a not-terribly-insane example of a MY::postamble in a footer
Dist-Zilla-Plugin-MakeMaker-Awesome-0.26

    - new 'preamble' and 'postamble' options renamed to 'header' and 'footer',
      to avoid confusion with MY::preamble and MY::postamble