Simplify example documentation of local filters

* doc/org.texi (Advanced configuration): Simplify example of local
filters, using #+BIND.
Update the guide and make it more compact
ox-md: Add publishing function to back-end
Add publishing capabilities to markdown backend

* lisp/ox-md.el (org-md-publish-to-md): New function.

TINYCHANGE

Patch by Brice Waegenire
Merge branch 'master' of orgmode.org:org-mode
Protect src overlay during saving the src snipped

* lisp/org-src.el (org-edit-src-exit): Let overlay survive after the
buffer has been saved.
Merge branch 'maint'
Honor user request for full-frame agenda window

* lisp/org-agenda.el (org-agenda-fit-window-to-buffer): Enforce
value 1.0 for minimum window height.
un-hexify TEL links in vCard export

This is required as a plus sign (e.g. +49 for germany) will cause
hexification in the link helper.

contrib/lisp/org-contacts.el: unhexify tel link

TINYCHANGE
Initial version of ABC notation handling for Babel
improve handling of output file types
ox: Ignore text before first headline with an :export: tag

* lisp/ox.el (org-export--populate-ignore-list): Ignore text before
  first headline if an :export: tag (or a select tag) is found within
  the buffer.
* testing/lisp/test-ox.el: Add tests.
don't add "set datafile missing..." with :missing

* lisp/ob-gnuplot.el (org-babel-expand-body:gnuplot): Don't add "set
  datafile missing..." with :missing, instead this header argument now
  only changes the value of the *org-babel-gnuplot-missing* variable.
ox-md: Do not define `org-md-publish-to-md' twice

* lisp/ox-md.el (ox-md-publish-to-md): Do not define function twice.
ox: Add a defcustom to export properties drawers

* lisp/ox.el (org-export-with-drawers): Improve docstring.
(org-export-with-properties): New variable
(org-export--skip-p): Handle new variable.
(org-export-options-alist): Install new variable.
* lisp/ox-ascii.el (org-ascii-node-property,
  org-ascii-property-drawer): New functions.
* lisp/ox-html.el (org-html-node-property): New function.
(org-html-property-drawer): Export property drawers as "pre" blocks.
* lisp/ox-latex.el (org-latex-property-drawer,
  org-latex-node-property): New functions.
* lisp/ox-man.el (org-man-node-property, org-man-property-drawer): New
  functions.
* lisp/ox-md.el (org-md-node-property, org-md-property-drawer): New
  functions.
* lisp/ox-odt.el (org-odt-node-property): New function.
(org-odt-property-drawer): Export property drawers as fixed width
blocks.
* lisp/ox-texinfo.el (org-texinfo-node-property): New function.
(org-texinfo-property-drawer): Export property drawers as verbatim
blocks.
* doc/org.texi: Update manual.
* testing/lisp/test-ox.el: Add tests.
Fix file bug in ox-freemind.el

* contrib/lisp/ox-freemind.el (org-freemind-export-to-freemind):
Remove spurious comma.
contrib/lisp/ox-rss.el (org-rss-headline): Add the <author> sub-element

* contrib/lisp/ox-rss.el (org-rss-headline): Add the <author> sub-element.
ox: Propagate property drawer changes to back-ends in contrib/

* contrib/lisp/ox-confluence.el (org-confluence-property-drawer): New
  function.
* contrib/lisp/ox-groff.el (org-groff-node-property,
  org-groff-property-drawer): New functions.
org.texi: Update Drawers section
contrib/lisp/ox-rss.el (org-rss-publish-to-rss): Create id when publishing

* contrib/lisp/ox-rss.el (org-rss-publish-to-rss): Create id
when publishing.