another gtk-properties addition

[Matthias Clasen <maclas gmx de>]

Hi,

the addition of a couple of new settings and a new style property have
again caused a couple of string additions to gtk-properties. This should
not be problematic, since the strings are not normally user-visible.

On the positive side, I think there is only one more possibly
string-changing bug on the GTK 2.4 willfix list.

Matthias