message: add clear for svg painter
diff: @@ -236,6 +236,12 @@ define(function (require) {
  this._svgRoot =
  this._viewport =
  this.storage = null;
  + },
  +
  + clear: function () {
  + if (this._viewport) {
  + this.root.removeChild(this._viewport);
  + }
  }
  }
  