flow(flow) {
    var _flow = flow;

    if (flow === "scrolled" || flow === "scrolled-doc" || flow === "scrolled-continuous") {
      _flow = "scrolled";
    }

    if (flow === "auto" || flow === "paginated") {
      _flow = "paginated";
    }

    this.settings.flow = flow;

    if (this._layout) {
      this._layout.flow(_flow);
    }

    if (this.manager && this._layout) {
      this.manager.applyLayout(this._layout);
    }

    if (this.manager) {
      this.manager.updateFlow(_flow);
    }

    if (this.manager && this.manager.isRendered() && this.location) {
      this.manager.clear();
      this.display(this.location.start.cfi);
    }
  }
Adjust the flow of the rendition to paginated or scrolled
(scrolled-continuous vs scrolled-doc are handled by different view managers)
@param  {string} flow