Export back-ends: Install smart quotes module

Export back-ends: Install smart quotes module

* contrib/lisp/org-e-ascii.el (org-e-ascii-plain-text): Install smart
  quotes module.
* contrib/lisp/org-e-html.el (org-e-html-plain-text): Install smart
  quotes module.  Fix :preseve-breaks option.
(org-e-html--quotation-marks): Remove function.
(org-e-html-quotes): Remove variable.
* contrib/lisp/org-e-latex.el (org-e-latex-plain-text): Install smart
  quotes module.
(org-e-latex--quotation-marks): Remove function.
(org-e-latex-quotes): Remove variable.
* contrib/lisp/org-e-odt.el (org-e-odt-plain-text): Install smart
  quotes module.
(org-e-odt--quotation-marks): Remove function.
(org-e-odt-quotes): Remove variable.
* contrib/lisp/org-md.el (org-md-plain-text): Install smart quotes
  module.  Fix characters escaping.
* contrib/lisp/org-e-texinfo.el (org-e-texinfo-center-block,
  org-e-texinfo-special-block): new functions.
(org-e-texinfo-quotes): Remove variable.
(org-e-texinfo--quotations-marks): Remove function.
(org-e-texinfo-plain-text): Install smart quotes module.
* contrib/lisp/org-e-groff.el (org-e-groff-plain-text): Install smart
quotes module.  Fix line break preservation.
(org-e-groff--quotation-marks): Remove function.
(org-e-groff-quotes): Remove variable.
(org-e-groff-entity): Fix property name.
* contrib/lisp/org-e-man.el (org-e-man-entity): Fix property name.
(org-e-man-plain-text): Install smart quotes module.  Fix line break
preservation.
(org-e-man-quotes): Remove variable.
(org-e-man--quotation-marks): Remove function.