GtkSwitch was listening for Space/Enter keyreleases itself, instead
of providing an 'activate' action signal, like e.g GtkButton. As a
side-effect, this fixes
https://bugzilla.gnome.org/show_bug.cgi?id=643321
Thomas Wood pointed out that the original MxGtkLightSwitch widget upon
which I based the behaviour of GtkSwitch was not written by him; the
original authors are:
Joshua Lock
Robert Staudinger
Jussi Kukkonen
My apologies to all of them.
The GtkSwitch widget is a simple UI control that has two states: on and
off. Toggling between the states is possible by clicking the widget or
by dragging the handle.
https://bugzilla.gnome.org/show_bug.cgi?id=634987
