Timestamp package replacement. Some enhancements. Some

Timestamp package replacement.  Some enhancements.  Some
XEmacs compatibility.  Doc Fix.
(ps-print-version): New version number (6.4).
(ps-printer-name): Initialization fix.
(ps-zebra-stripe-follow): Funcionality enhancement.
(ps-prologue-file): Code enhancement.
(ps-right-header): Timestamp package replacement.
(ps-setup, ps-face-bold-p, ps-face-italic-p, ps-get-page-dimensions)
(ps-generate-header, ps-begin-file, ps-begin-job)
(ps-generate-postscript-with-faces, ps-do-despool): Code fix.
(ps-time-stamp-mon-dd-yyyy, ps-time-stamp-hh:mm:ss): New funs.
(ps-zebra-stripe-full-p, ps-zebra-stripe-alist): New vars.
(coding-system-for-write): Var declaration (XEmacs compatibility).