Move default_app to root of repo

default_app/default_app.js

@@ -0,0 +1,23 @@
+const electron = require('electron');
+const app = electron.app;
+const BrowserWindow = electron.BrowserWindow;
+
+var mainWindow = null;
+
+// Quit when all windows are closed.
+app.on('window-all-closed', function() {
+  app.quit();
+});
+
+exports.load = function(appUrl) {
+  app.on('ready', function() {
+    mainWindow = new BrowserWindow({
+      width: 800,
+      height: 600,
+      autoHideMenuBar: true,
+      useContentSize: true,
+    });
+    mainWindow.loadURL(appUrl);
+    mainWindow.focus();
+  });
+};