message: add bottomless to dome
diff: public paths: IPathMap = {};
  - constructor(width: number, height: number, radius?: number) {
  + constructor(width: number, height: number, radius?: number, bottomless?: boolean) {
  var w2 = width / 2;
  var wt = Math.max(w2 - radius, 0);
  var hr = Math.max(height - radius, 0);
  + if (!bottomless) {
  this.paths["Bottom"] = new paths.Line([-w2, 0], [w2, 0]);
  + }
  if (hr) {
  this.paths["Left"] = new paths.Line([-w2, 0], [-w2, hr]);
  (<IKit>Dome).metaParameters = [
  { title: "width", type: "range", min: 1, max: 100, value: 50 },
  { title: "height", type: "range", min: 1, max: 100, value: 100 },
  - { title: "radius", type: "range", min: 0, max: 50, value: 25 }
  + { title: "radius", type: "range", min: 0, max: 50, value: 25 },
  + { title: "bottomless", type: "bool", value: false }
  ];
  }
  