(ps-mule-font-info-database): Doc-string modified.

(ps-mule-font-info-database): Doc-string modified.
(ps-mule-external-libraries): New element FEATURE.
(ps-mule-init-external-library): Ajusted for the above change.
(ps-mule-generate-font): Likewise.
(ps-mule-generate-glyphs): Likewise.
(ps-mule-prepare-font): Likewise.
(ps-mule-initialize): Likewise.
(ps-begin-file): Superfluous tailing parenthesis deleted.

Mule related code moved to ps-mule.el.
(ps-begin-job): While setting ps-control-or-escape-regexp, don't
check ps-mule-charset-list.
(ps-begin-page): Don't set ps-mule-current-charset, instead call
ps-mule-begin-page.
(ps-basic-plot-string): Call ps-mule-prepare-ascii-font.
(ps-plot-region): Don't set ps-mule-current-charset, instead call
ps-mule-set-ascii-font.  Don't call ps-mule-skip-same-charset,
instead skip same charsets by itself.
(ps-generate): Call ps-mule-initialize of needs-begin-file is
non-nil.  Call ps-mule-begin-job.

(ps-print-version): New version number (4.1.2), doc fix
and mule related code extraction. Autoload ps-mule funs.

Define several functions for Emacs 20.2 and the
earlier version.
(ps-printer-name): Check if printer-name is bound.