fix(quit): Booleans on globals are not exposed through remote properly

src/browser/application.es6

@@ -72,6 +72,10 @@ export default class Application extends EventEmitter {
     return this.windowManager.get(WindowManager.MAIN_WINDOW).browserWindow;
   }
 
+  isQuitting() {
+    return this.quitting;
+  }
+
   temporaryInitializeDisabledPackages() {
     if (this.config.get('core.disabledPackagesInitialized')) {
       return;

src/browser/nylas-window.coffee

@@ -148,8 +148,7 @@ class NylasWindow
     #
     # This uses the DOM's `beforeunload` event.
     @browserWindow.on 'close', (event) =>
-      if @neverClose and !global.application.quitting
-
+      if @neverClose and !global.application.isQuitting()
         # For neverClose windows (like the main window) simply hide and
         # take out of full screen.
         event.preventDefault()

src/window-event-handler.coffee

@@ -37,6 +37,8 @@ class WindowEventHandler
     window.onbeforeunload = =>
       # Don't hide the window here if we don't want the renderer process to be
       # throttled in case more work needs to be done before closing
+
+      # In Electron, returning false cancels the close.
       return @runUnloadCallbacks()
 
     window.onunload = =>
@@ -122,7 +124,7 @@ class WindowEventHandler
   runUnloadFinished: ->
     {remote} = require('electron')
     _.defer ->
-      if remote.getGlobal('application').quitting
+      if remote.getGlobal('application').isQuitting()
         remote.app.quit()
       else
         NylasEnv.close()