Removed via regex and grep.

The following were intentionally not removed:

- GtkImage:file: (attributes org.gtk.Property.set=gtk_image_set_from_file)
- GtkImage:resource: (attributes org.gtk.Property.set=gtk_image_set_from_resource)

As they have no getter and (setter PROP) without a (getter PROP) crash
gobject-introspection. This is fixed by
gobject-introspection@ad3118eb.