gesture: report one event at a time

Events are now delivered one at a time, and this change makes the
corresponding change to gestures.

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

gesture/gesture_test.go

@@ -77,8 +77,16 @@ func TestMouseClicks(t *testing.T) {
 			r.Frame(&ops)
 			r.Queue(tc.events...)
 
-			events := click.Update(r.Source())
-			clicks := filterMouseClicks(events)
+			var clicks []ClickEvent
+			for {
+				ev, ok := click.Update(r.Source())
+				if !ok {
+					break
+				}
+				if ev.Kind == KindClick {
+					clicks = append(clicks, ev)
+				}
+			}
 			if got, want := len(clicks), len(tc.clicks); got != want {
 				t.Fatalf("got %d mouse clicks, expected %d", got, want)
 			}
@@ -108,13 +116,3 @@ func mouseClickEvents(times ...time.Duration) []event.Event {
 	}
 	return events
 }
-
-func filterMouseClicks(events []ClickEvent) []ClickEvent {
-	var clicks []ClickEvent
-	for _, ev := range events {
-		if ev.Kind == KindClick {
-			clicks = append(clicks, ev)
-		}
-	}
-	return clicks
-}