po4a (convert PO to/from other documentation formats)

po4a (PO for anything) eases translations and their maintenance,
allowing gettext's usage on unexpected areas like documentation.

In po4a each documentation format is handled by a module that converts
this format to/from PO. Formats handled by po4a:

- asciidoc: AsciiDoc format.
- dia: uncompressed Dia diagrams.
- docbook: DocBook XML.
- guide: Gentoo Linux's XML documentation format.
- ini: INI format.
- kernelhelp: Help messages of each kernel compilation option.
- latex: LaTeX format.
- man: Good old manual page format.
- pod: Perl Online Documentation format.
- sgml: either DebianDoc or DocBook DTD.
- texinfo: The info page format.
- tex: generic TeX documents (see also latex).
- text: simple text document.
- wml: WML documents.
- xhtml: XHTML documents.
- xml: generic XML documents (see also docbook).
- yaml: YAML documents.

man pages are encoded in UTF-8. To read them in other languages than
English, do this for instance:
LANG=ru_RU.utf8 GROFF_ENCODING=utf8 man <man page>

See README_SBo.txt for dependency info and build options.