message: Support handler that called at last in eventful.
diff: @@ -264,12 +264,21 @@ function on(eventful, event, query, handler, context, isOnce) {
  }
  }
  - _h[event].push({
  + var wrap = {
  h: handler,
  one: isOnce,
  query: query,
  - ctx: context || eventful
  - });
  + ctx: context || eventful,
  + // FIXME
  + // Do not publish this feature util it is proved that it makes sense.
  + callAtLast: handler.zrEventfulCallAtLast
  + };
  +
  + var lastIndex = _h[event].length - 1;
  + var lastWrap = _h[event][lastIndex];
  + (lastWrap && lastWrap.callAtLast)
  + ? _h[event].splice(lastIndex, 0, wrap)
  + : _h[event].push(wrap);
  return eventful;
  }
  