Set parent window for about/new version, escape to close (#1795)

* Set parent window for about/new version, escape to close

* Exclude jquery from jshint run

main.js

@@ -22,6 +22,10 @@ app.setAppUserModelId('org.whispersystems.signal-desktop')
 // be closed automatically when the JavaScript object is garbage collected.
 let mainWindow;
 
+function getMainWindow() {
+  return mainWindow;
+}
+
 const config = require("./app/config");
 
 if (config.environment === 'production' && !process.mas) {
@@ -241,7 +245,8 @@ function showAbout() {
     webPreferences: {
       nodeIntegration: false,
       preload: path.join(__dirname, 'preload.js')
-    }
+    },
+    parent: mainWindow,
   };
 
   aboutWindow = new BrowserWindow(options);
@@ -269,7 +274,7 @@ app.on('ready', function() {
     locale = loadLocale();
   }
 
-  autoUpdate.initialize(locale.messages);
+  autoUpdate.initialize(getMainWindow, locale.messages);
 
   createWindow();
 
@@ -342,3 +347,10 @@ ipc.on("set-auto-hide-menu-bar", function(event, autoHide) {
 ipc.on("set-menu-bar-visibility", function(event, visibility) {
   mainWindow.setMenuBarVisibility(visibility);
 });
+
+ipc.on("close-about", function() {
+  if (aboutWindow) {
+    aboutWindow.close();
+  }
+});
+