Replace it with a dummy event send on the synchronous event channel;
a bit of cleverness for a simpler API.
Signed-off-by: Elias Naur <mail@eliasnaur.com>
Gio doesn't support multiple windows anyway, so get rid of the
app.Windows channel and use NewWindow call for the mobile platforms
as well.
Signed-off-by: Elias Naur <mail@eliasnaur.com>