Add minimal checkbox

UI/Base/CheckBox.ts

@@ -0,0 +1,17 @@
+import {UIElement} from "../UIElement";
+import {UIEventSource} from "../UIEventSource";
+
+
+export class CheckBox extends UIElement{
+
+    constructor(data: UIEventSource<boolean>) {
+        super(data);
+        
+    }
+
+
+    protected InnerRender(): string {
+        return "";
+    }
+    
+}