Clarify the wintty purpose and syntax.

  Still some todos: an option to just abort user feedback and close the
  window instantly upon loosing the stdin pipe, allow the stdin pipe to
  be tee'ed on win32, and still add some graceful error handling for a
  real-world deployment.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@89110 13f79535-47bb-0310-9956-ffa450edef68