removeTileWithFade(tileSprite, fadeDuration) {
    if (fadeDuration == null) { fadeDuration = CONFIG.FADE_FAST_DURATION; }
    this.removeTile(tileSprite, fadeDuration);
  }
Removes a tile by fading.
@param {cc.Node} tileSprite
@param {Number} fadeDuration seconds over which to fade tile