PostScript code now is in separate files, doc fix.

PostScript code now is in separate files, doc fix.
(ps-print-version): New version number (5.0.3).
(ps-header-lines, ps-left-header, ps-right-header): No more buffer
local.
(ps-spool-config): Initialization fix.
(ps-print-prologue-1, ps-print-prologue-2, ps-print-duplex-feature):
PostScript code moved to separated file.
(ps-background-image): Little code reformating.
(ps-begin-file, ps-begin-job): Fix code.
(ps-postscript-code-directory, ps-mark-code-directory): New
vars.
(ps-prologue-file): New fun.