code: function setMuted(x, y, z) {
           this._x = x;
           this._y = y;
           this._z = z;
           return this;
         }
docs: set the vector value without triggering the callback
  @name setMuted
  @memberOf me.ObservableVector3d
  @function
  @param {Number} x x value of the vector
  @param {Number} y y value of the vector
  @param {Number} z z value of the vector
  @return {me.ObservableVector3d} Reference to this object for method chaining