Add mechanism to get the AutoUpdateManager's state

src/browser/atom-application.coffee

@@ -307,6 +307,9 @@ class AtomApplication
     ipcMain.on 'check-for-update', =>
       @autoUpdateManager.check()
 
+    ipcMain.on 'get-auto-update-manager-state', (event) =>
+      event.returnValue = @autoUpdateManager.getState()
+
     ipcMain.on 'execute-javascript-in-dev-tools', (event, code) ->
       event.sender.devToolsWebContents?.executeJavaScript(code)