Goffice and cairo

[Emmanuel Pacaud <emmanuel pacaud univ-poitiers fr>]

Hi,

I would like to make cairo a dependency of goffice HEAD.

I'm working on the graph cairo renderer for quite some time now, and is
in good shape with just one known regression with respect to
libart/gnomeprint/svg renderers 
( see http://bugzilla.gnome.org/show_bug.cgi?id=341993 ). It even adds
some nice additionnal features like mutiline labels in svg export,
pretty log axis labels, and ps/pdf export.

This would also allow me to use the new GOPalette/GOSelector widgets.
They're prettier than GOCombo, use less code, support drag and drop and
make switching objects in guru dialog snappier (and with a bit of work,
it will be possible to replace completely GOCombo and derivated
widgets).

This new dependency can be added without requiring a newer version of
gtk+, which means we can keep gtk+ 2.6 (That's better for the maemo port
of gnumeric, where gtk+ > 2.6 is not possible yet).

If it's ok, I'll change configure file in order to add a hard dependency
to cairo 1.2.0 (which is a version with acceptable ps/pdf/svg backends).

        Emmanuel.