* contrib/lisp/org-e-ascii.el (org-e-ascii--build-caption,
org-e-ascii--list-listings, org-e-ascii--list-tables): Use new
caption tool.
* contrib/lisp/org-e-latex.el (org-e-latex--caption/label-string): New
signature. Use new caption tool.
(org-e-latex-link--inline-image, org-e-latex-src-block,
org-e-latex-table--org-table): Apply signature change.
* contrib/lisp/org-md.el (org-md-link): Use new caption tool.
* contrib/lisp/org-e-ascii.el: Add an entry for `org-export-dispatch'.
* contrib/lisp/org-e-beamer.el: Add an entry for `org-export-dispatch'.
* contrib/lisp/org-e-groff.el (e-groff): Use
`org-export-define-backend'. Add an entry for `org-export-dispatch'.
* contrib/lisp/org-e-html.el: Add an entry for `org-export-dispatch'.
* contrib/lisp/org-e-latex.el: Add an entry for `org-export-dispatch'.
* contrib/lisp/org-e-man.el: Use `org-export-define-backend'. Add an
entry for `org-export-dispatch'.
* contrib/lisp/org-e-odt.el: Add an entry for `org-export-dispatch'.
* contrib/lisp/org-e-texinfo.el: Use `org-export-define-backend'. Add an
entry for `org-export-dispatch'.
* contrib/lisp/org-md.el: Add an entry for `org-export-dispatch'.
* lisp/org-element.el (org-element-link-type-is-file): New variable.
(org-element-link-parser): Extract search option and application in
"file"-type links.
* contrib/lisp/org-e-html.el (org-e-html-link): Remove components
extraction since this in now done in `org-element-link-parser'.
* contrib/lisp/org-e-odt.el: Remove components extraction since this
in now done in `org-element-link-parser'.
* contrib/lisp/org-e-texinfo.el (org-e-texinfo-link): Remove
components extraction since this in now done in
`org-element-link-parser'.
* contrib/lisp/org-e-latex.el (org-e-latex-link): Remove components
extraction since this in now done in `org-element-link-parser'.
* contrib/lisp/org-e-man.el (org-e-man-link): Remove components
extraction since this in now done in `org-element-link-parser'.
* contrib/lisp/org-e-groff.el (org-e-groff-link): Remove components
extraction since this in now done in `org-element-link-parser'.
* contrib/lisp/org-md.el (org-md-link): Remove components extraction
since this in now done in `org-element-link-parser'.
* testing/lisp/test-org-element.el: Add tests.
* contrib/lisp/org-md.el (org-export-md): New customize group.
(org-md-headline-style): New variable.
(org-md-headline): Allow atx and Setext style. Also provide fall-back
for low level headlines.
* contrib/lisp/org-md.el (org-md-section): # protection shouldn't
happen at the section level, when there is no difference between raw
# from export blocks and # in plain text.
* contrib/lisp/org-md.el (org-md-paragraph, org-md-plain-text): Make
sure raw # (inserted with, for example, an export snippet) don't get
escaped. A few false positives don't hurt.