message: Support rendered event.
diff: @@ -241,12 +241,18 @@ ZRender.prototype = {
  * Perform all refresh
  */
  flush: function () {
  + var triggerRendered;
  +
  if (this._needsRefresh) {
  + triggerRendered = true;
  this.refreshImmediately();
  }
  if (this._needsRefreshHover) {
  + triggerRendered = true;
  this.refreshHoverImmediately();
  }
  +
  + triggerRendered && this.trigger('rendered');
  },
  /**
  