ps-samp.el: Make it slightly less awful

ps-samp.el: Make it slightly less awful

* lisp/ps-samp.el (ps-rmail-mode-hook, ps-gnus-article-prepare-hook)
(ps-vm-mode-hook, ps-gnus-summary-setup, ps-info-mode-hook):
Use [print] key.  Only set local values.
(ps-article-subject, ps-article-author): Use standard functions
like mail-fetch-field.
(ps-info-file, ps-info-node): Use match-string.
(ps-jts-ps-setup, ps-jack-setup): Remove, merging into...
(ps-samp-ps-setup): ... new function.