gdk-pixbuf reference

["Matthias Clasen" <matthiasc poet de>]

I'm sorry to notice that my commit from yesterday broke the gdk-pixbuf
reference on d.g.o.
The reason is that I introduced an entity named initialization_versions and
overlooked that
'_' is not a namechar in the docbook 3.0 declaration. Unfortunately, I won't
have occasion
to fix this in the next two weeks, because we're on the leave for a
vacation.

The two possible fixes are:

1) s/_/-/g for the names of the newly-added entities

2) switch to docbook 4.1 (and wait till the autobuilder on d.g.o gets
docbook-4.1-enabled)

I would prefer 2), since we need it anyway in the long run (to get the PNG
notation, for one thing)

Matthias