gtkdialog: Allow specifying response IDs by nick in <action-widgets>
gtkdialog: Allow specifying response IDs by nick in <action-widgets>

This makes it a lot more convenient for developers, as they don't
have to look up the numeric value of response IDs.

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