reference to alias data changed into getters

frontend-js/src/main/js/map/marker/AliasMarker.js

@@ -40,8 +40,8 @@ AliasMarker.prototype.setAliasData = function (data) {
  * @returns {google.maps.Point} - coordinates where marker is pointing
  */
 AliasMarker.prototype.getCoordinates = function () {
-  return new google.maps.Point(this._aliasData.x + this._aliasData.width / 2, this._aliasData.y
-    + this._aliasData.height / 2);
+  var alias = this.getAliasData();
+  return new google.maps.Point(alias.getX() + alias.getWidth() / 2, alias.getY() + alias.getHeight() / 2);
 };
 
 AliasMarker.prototype.init = function () {