title: fire event when touch up inside uiview and outside button
body: <p>I have a view overlayed to the iPhone's camera view. In this view I have some uibuttons that are displayed in positions depending of values from accelerometer/compass.
  I need to fire an event when the user touch up inside the view but he doesn't touch up inside the uibuttons, I mean, the opposite action of touch up inside the uibuttons.
  Anyone knows a kind to do this?
  Thanks! </p>