* lisp/ox-html.el (org-html--format-toc-headline): Make use of
anonymous back-ends.
* lisp/ox-odt.el (org-odt-footnote-reference): Make use of anonymous
back-ends.
(org-odt-format-label, org-odt-toc, org-odt-format-headline--wrap):
Use `org-export-with-backend' instead of
`org-export-with-translations'.
* contrib/lisp/ox-freemind.el (org-freemind--build-node-contents): Use
`org-export-with-backend' instead of `org-export-with-translations'.
* contrib/lisp/ox-freemind.el: New file.
* lisp/ox-html.el (org-html--tags, org-html-format-headline)
(org-html--format-toc-headline, org-html-checkbox)
(org-html-table-cell, org-html-timestamp)
(org-html-verse-block, org-html-special-string-regexps):
Replace named HTML entities with their numeric counterparts.
This keeps Freemind backend happy.