PointCloudLayer - change point size and density

var pointCloudRGBRenderer = {
  type: "point-cloud-rgb", // autocasts as new pointCloudRGBRenderer()
  field: "RGB",
  pointSizeAlgorithm: {
    type: "fixed-size",
    useRealWorldSymbolSizes: false,
    size: 10
  },
  pointsPerInch: 15
};