Preparation for porting to GTK3 in GTK+ 2, part 2

[qarkai]

• Replace deprecated functions
• Replace removed in GTK3 GdkDrawable and GtkObject

[hellosiyan]

Thank you for your continued support and work, @qarkai! You have found and fixed some small issues like the Combo Box, unused variables, etc :+1: . But I do not understand the change from GdkDrawable to GdkWindow :thinking: GdkWindow references are passed to functions expecting GdkDrawable, like gdk_draw_pixbuf. As far as I understand GdkWindow is a subtype of GdkDrawable, but aren't there any negative effects of passing the "wrong reference"?

Thanks again!

[qarkai]

1. It's OK to use subclass. Calling function will a) check parent type (subclass pass it), b) use parent type's methods (subclass has them).
2. GdkDrawable is gone in GTK3.