Handle before-string and after-string overlay properties

Handle before-string and after-string overlay properties
in ps-print-*-with-faces commands.  Doc fix.
(ps-print-version): New version number (6.5.2).
(ps-e-overlay-end): Alias for overlay-end to avoid compilation gripes
for XEmacs.
(ps-prefix-quote): Doc fix.
(ps-setup, ps-print-quote, ps-generate-postscript-with-faces): Code
fix.
(ps-basic-plot-str, ps-plot-string): New funs.