The great plugin renaming in the name of inheritance and standardization commit.
1. new concept of standard hook_ names.
2. Plugin::init
3. renamed many subroutines in plugins (and cleaned up register subs)
4. updated README.plugins
git-svn-id: https://svn.perl.org/qpsmtpd/trunk@479 958fd67b-6ff1-0310-b445-bb7760255be9
