Fix some visibilities in chart.ts

src/ts/chart-base/chart.ts

@@ -2,11 +2,11 @@ import * as d3 from 'd3';
 import { ChartConfiguration } from './chart-configuration';
 
 export abstract class Chart {
-    protected config: ChartConfiguration;
+    public config: ChartConfiguration;
     public data: any[];
-    protected width: number;
-    protected height: number;
-    protected svg: d3.Selection<d3.BaseType, unknown, HTMLElement, any>;
+    public width: number;
+    public height: number;
+    protected svg: any;
     protected chart: any;