Renamed do-when-up to be when-up.

  This seems saner to me.
  Updated comments/usage.

 These now refer to the new name `when-up`, rather than `do-when-up`.
  Moved when-up section to correct place.

  Since it was renamed it now belongs in the `w`-section.
  Updated to use /bin/sh

  By dropping the fancy positional-argument extraction, and using
 `shift` we can run under dash, etc.
  Mention the trivial alternative to when-up
  [PATCH] Fix randpass -f 2 to not produce empty passwords

The echo builtin interprets "-e" and "-n" which can lead randpass into
generating empty passwords under some conditions. This patch uses
the printf builtin instead to avoid the issue.

(From a private mail from Timo Juhani Lindfors).
fix whitespace
Merge pull request #5 from atweiden/master

fix whitespace - Thanks for your contribution :)