io/input: implement lazy event routing

This change defers event routing from the time the event is queued until
the time Events is called. This allows a future change to execute
commands immediately and to react to event order changes during a frame.

Signed-off-by: Elias Naur <mail@eliasnaur.com>

app/window.go

@@ -319,7 +319,7 @@ func (w *Window) processFrame(d driver) {
 	if mime, txt, ok := q.WriteClipboard(); ok {
 		d.WriteClipboard(mime, txt)
 	}
-	if q.ReadClipboard() {
+	if q.ClipboardRequested() {
 		d.ReadClipboard()
 	}
 	oldState := w.imeState