is not ready for integration
This commit makes the native-layout branch into a reasonable
patch applicable to git master, it pulls out GtkCellRenderer
support, ComboBox support, the Plug/Socket api is also not ready
and is pulled out.
Currently get_desired_size() is more of an emulation of
gtk_widget_size_request() for the minimum size as it bases the
contextual request on the minimum preferred size; this argument
lets you do the request with the natural preferred size as well.
This commit changes gtk_extended_layout_get_desired_size() for
per dimension variants. Furthermore this commit reverts the actions
done in size-groups for now as it needs a different approach.
The natural width/height parameters added to aux_info have been changed
for a per width cache for heights and a per height cache for widths.
gtk-demo is still working, currently sizegroups are not taken
into account as mentioned above - size groups need to be alerted both
when the widths and heights are updated independantly and then that
information needs to repropagate also to other extended layout implementors.
Added an indicator telling whether a widget prefers to be allocated
as height-for-width or width-for-height. Usually this depends on the
orientation of a container or the nature of a content widget like GtkLabel.
This indicator is only used in the seldom case where a parent is allocating
free space to the child and the child can flow in either direction, GtkWindow
and GtkScrolledWindow are users of this api.
