Even/odd pages fix. Fix little bug on XEmacs. Avoid

Even/odd pages fix.  Fix little bug on XEmacs.  Avoid
compilation gripes.  Doc fix.
(ps-print-version): New version number (6.2).
(ps-x-color-instance-p, ps-x-color-instance-rgb-components)
(ps-x-color-name, ps-x-color-specifier-p, ps-x-copy-coding-system)
(ps-x-device-class, ps-x-extent-end-position, ps-x-extent-face)
(ps-x-extent-priority, ps-x-extent-start-position)
(ps-x-face-font-instance, ps-x-find-coding-system)
(ps-x-font-instance-properties, ps-x-make-color-instance)
(ps-x-map-extents): Alias for functions without the prefix `ps-x-', to
avoid compilation gripes without defining functions.
(ps-e-find-composition): Alias for function find-composition, to have a
suitable function depending on Emacs version.
(ps-color-device, ps-color-values, ps-face-foreground-name)
(ps-face-background-name, ps-face-bold-p, ps-face-italic-p, ps-mapper)
(ps-extent-sorter, ps-xemacs-face-kind-p, ps-xemacs-color-name)
(ps-print-ensure-fontified): Function definitions surrounded by
`eval-and-compile' to avoid compilation gripes.
(ps-font-lock-face-attributes): `font-lock-face-attributes' evaluated
by symbol-value to avoid compilation gripes.
(ps-end-file, ps-header-sheet, ps-plot-region): Even/odd pages fix.
(ps-generate-postscript-with-faces): Fix little bug on XEmacs.