determineLayoutProperties(metadata) {
    var properties;
    var layout = this.settings.layout || metadata.layout || "reflowable";
    var spread = this.settings.spread || metadata.spread || "auto";
    var orientation = this.settings.orientation || metadata.orientation || "auto";
    var flow = this.settings.flow || metadata.flow || "auto";
    var viewport = metadata.viewport || "";
    var minSpreadWidth = this.settings.minSpreadWidth || metadata.minSpreadWidth || 800;
    var direction = this.settings.direction || metadata.direction || "ltr";

    if ((this.settings.width === 0 || this.settings.width > 0) && (this.settings.height === 0 || this.settings.height > 0)) {// viewport = "width="+this.settings.width+", height="+this.settings.height+"";
    }

    properties = {
      layout: layout,
      spread: spread,
      orientation: orientation,
      flow: flow,
      viewport: viewport,
      minSpreadWidth: minSpreadWidth,
      direction: direction
    };
    return properties;
  }
Determine the Layout properties from metadata and settings
@private
@param  {object} metadata
@return {object} properties