[PATCH] Fixing some docs build warnings

[Reinhold Kainhofer]

I'm currentlly trying to clean up some build warnings.

1) The xref-map generation didn't use the same includes as texi2html, so we 
got several warnings about files not found. The following patch should fix 
those:
http://codereview.appspot.com/5038044

2) A normal "make" tries to load the translations for the gettext domain 
"lilypond-doc" from the directory 
/home/reinhold/lilypond/lilypond/Documentation/po/out-www
As they are not created during a normal build, we get one warning for each 
file processed:

langdefs.py: warning: lilypond-doc gettext domain not found.

Can't we add the lilypond-doc gettext creation to the begin of a normal build, 
too?

3) A normal build also tries to create several info files with images in 
pictures, for which we do not have any *.txt files, resulting in warnings:

./contributor/programming-work.itexi:67: Warnung: @image-Datei 
„lilypond/pictures/architecture-diagram.txt“ (für Text) nicht lesbar: Datei 
oder Verzeichnis nicht gefunden.
./contributor/programming-work.itexi:67: Warnung: @image-Datei 
„lilypond/pictures/architecture-diagram.txt“ (für Text) nicht lesbar: Datei 
oder Verzeichnis nicht gefunden.

First, why do we hardcode the lilypond/ directory? AFAICS, we don't create or 
use that directory at all. All snippets link their images to something a0/... 
and not to lilypond/a0/... Only explicit image links have lilypond/ hardcoded 
in the macro.
And second, should we create a .txt file for each static .png image we use, so 
makinfo is happy?

4) The snippets texinfo has the problem that each snippets adds a @node with 
its name. If a snippet is included twice, we have duplicated nodes. Also, in 
each snippet category, we do not create any menu, but create a node for each 
snippet, so we have lots of notes that are not inside any menu. Any idea how 
to proceed with those?

Cheers,
Reinhold
-- 
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Reinhold Kainhofer, address@hidden, http://reinhold.kainhofer.com/
 * Financial & Actuarial Math., Vienna Univ. of Technology, Austria
 * http://www.fam.tuwien.ac.at/, DVR: 0005886
 * LilyPond, Music typesetting, http://www.lilypond.org