org: add an example of conversion to BA format
This script was first posted on https://github.com/adl/hoaf/issues/73
- doc/org/tut25.org: New file.
- doc/Makefile.am: Add it.
- doc/org/tut.org, doc/org/tut21.org, NEWS: Link to it.
- doc/org/init.el.in: Install *.py files.
- doc/org/.gitignore: Add toba.py.