title: removing Objects from an event in Corona SDK
body: <p>So I'm creating a game where an enemy is firing a bullet.  The bullet eventrully hits a collision I made, when it hits the end of the screen.  Im wanting at this point to remove it and clear the address back to a nil value.  When checking the address before and after the collision, no change was made.  please help with any insight you might have on this.</p>
  
  <pre><code>local onCollision = function(event)
          if event.phase == "began" then
              event.object2:removeSelf();
              event.object2 = nil;
          end
  end
  Runtime:addEventListener("collision",onCollision);
  </code></pre>