tabs fixes

src/components/nav-view/nav-view.js

@@ -0,0 +1,23 @@
+import {Ion} from '../ion'
+
+export class NavView extends Ion {
+
+  // viewControllers: Stack<ViewController>;
+  //   visibleViewController: ViewController;
+
+  //   push(viewController) {
+  //     stack.push(viewController)
+  //   }
+  //   pop(viewController) {
+  //     stack.pop(viewController)
+  //   }
+  //   set viewControllers(v) {
+  //     this.viewControllers = v
+  //   }
+
+  constructor() {
+    console.log('construct nav-view')
+    this.history = [] // <---- would be fancy pants
+  }
+
+}