This is meant as an input to the font chooser.
We don't want the user to select a language, but
rather have fonts presented as they would work for
the current language. Therefore, do away with the
lang/script combo on the tweak page.
We can't add properties to the interface, since it breaks
3rd party implementations of the GtkFontChooser interface.
These exist, for example in gnumeric.
So, instead of a new property, add getter/setter vfuncs.
This patch changes all uses of GDK_DEPRECATED(_FOR) in gtk headers
by the versioned variants, GDK_DEPRECATED_IN_3_x(_FOR). At the same
time, we add GDK_AVAILABLE_IN_3_x annotations for all API additions
in 3.2 and 3.4.
The setter for the "font" property returned a boolean that indicated
whether the given font has been found. Instead, fall back to the default
font name when the given font doesn't exist.
GtkFontButton already has a property named "font-name" which may
conflict / be an ABI break when moving GtkFontButton to implement
GtkFontChooser. Also, this is more in line with how other parts in
gtk (e.g. GtkCellRendererText) call a font string property.
Make the GtkFontChooser API similar to the Gtk{File,Recent,App}Chooser
APIs by introducing GtkFontChooser as an interface, that has a default
implementation in GtkFontChooserWidget.
https://bugzilla.gnome.org/show_bug.cgi?id=657627
