gktsourceview3 test: use gtk3 and gkd3 instead of gtk2.
gktsourceview3 test: use gtk3 and gkd3 instead of gtk2.

gtksourceview3 depends gdk3 and gtk3.

kitachro/ruby-gnome2,kitachro/ruby-gnome2,kitachro/ruby-gnome2,kitachro/ruby-gnome2,kitachro/ruby-gnome2