Fixes a small bug in Flower.TouchHandler

If a TOUCH_DOWN event triggers a open scene, then the TOUCH_UP will be missed by the touch handler instance. This will cause the next TOUCH_DOWN to call an old touchProps[e.idx]. TOUCH_DOWN should never need to call a touchProps[e.idx].

1. TOUCH_DOWN 1: prop stored in touchProps, Eventhandler opens new scene in overlay mode

1. TOUCH_UP: is handled by the new scene's touch handler

1. Return to old scene

1. TOUCH_DOWN: sends message to current prop and the old one from TOUCH_DOWN 1