/// <summary>
/// Adds a notification port to the list of subscriptions that get notified when the bumper shapes
/// collide in the physics world
/// </summary>
/// <param name="notificationTarget"></param>
public void Subscribe(Port <EntityContactNotification> notificationTarget)
{
// the parent has the physics entity create (we are just part of that entity)
// so subscribe there.
PhysicsEntity.SubscribeForContacts(notificationTarget);
}