wayland: implement text_property_to_utf8_list()
wayland: implement text_property_to_utf8_list()

Of some sort, this is enough to get text transfers on wayland, anything but
utf8 as plain/text should be pretty rare.

https://bugzilla.gnome.org/show_bug.cgi?id=697855

chergert/gtk,davidgumberg/gtk,jigpu/gtk,chergert/gtk,alexlarsson/gtk,jigpu/gtk,jessevdk/gtk,Lyude/gtk-,ahodesuka/gtk,jessevdk/gtk,alexlarsson/gtk,grubersjoe/adwaita,Adamovskiy/gtk,Adamovskiy/gtk,alexlarsson/gtk,davidgumberg/gtk,Adamovskiy/gtk,jessevdk/gtk,ahodesuka/gtk,jadahl/gtk,davidgumberg/gtk,davidgumberg/gtk,jigpu/gtk,grubersjoe/adwaita,Adamovskiy/gtk,jigpu/gtk,jadahl/gtk,Adamovskiy/gtk,grubersjoe/adwaita,ahodesuka/gtk,grubersjoe/adwaita,alexlarsson/gtk,Lyude/gtk-,chergert/gtk,Lyude/gtk-,grubersjoe/adwaita,chergert/gtk,ahodesuka/gtk,grubersjoe/adwaita,Lyude/gtk-,chergert/gtk,chergert/gtk,jessevdk/gtk,jadahl/gtk,Lyude/gtk-,jessevdk/gtk,grubersjoe/adwaita,jigpu/gtk,ahodesuka/gtk,davidgumberg/gtk,jigpu/gtk,jadahl/gtk,ahodesuka/gtk,Lyude/gtk-,chergert/gtk,davidgumberg/gtk,davidgumberg/gtk,ahodesuka/gtk,davidgumberg/gtk,jigpu/gtk,Lyude/gtk-,Adamovskiy/gtk,jessevdk/gtk,alexlarsson/gtk,Lyude/gtk-,jadahl/gtk,alexlarsson/gtk,jigpu/gtk,Adamovskiy/gtk,alexlarsson/gtk,alexlarsson/gtk,Adamovskiy/gtk,jadahl/gtk,chergert/gtk,jadahl/gtk,ahodesuka/gtk,jessevdk/gtk,jadahl/gtk,grubersjoe/adwaita