gesture: Handle GDK_TOUCH_CANCEL events
gesture: Handle GDK_TOUCH_CANCEL events

The wayland windowing backend emits such events for instance, so
have gestures cancel the sequence as those events get through.

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