Move logout button to settings. Replace logout button in menu with shutdown button.

lib/base/base_state.dart

@@ -1,6 +1,5 @@
 import 'package:checker/resources.dart';
 import 'package:flutter/material.dart';
-import 'package:flutter/services.dart';
 
 import 'package:checker/common.dart';
 import 'package:checker/consts.dart';
@@ -70,14 +69,10 @@ abstract class BaseState<T extends StatefulWidget> extends State<T> {
       child: getMenuItem(help_png, StringsLocalization.help())
     ));
 
-    helper.getToken().then((token){
-      if (token != null) { // пользователь авторизован
-        menuItemList.add(new PopupMenuItem(
-          value: 2,
-          child: getMenuItem(logout_png, StringsLocalization.logout())
-        ));
-      }
-    });
+    menuItemList.add(new PopupMenuItem(
+      value: 2,
+      child: getMenuItem(exit_png, StringsLocalization.exit())
+    ));
 
     return <Widget>[
       new PopupMenuButton<int>(
@@ -100,7 +95,8 @@ abstract class BaseState<T extends StatefulWidget> extends State<T> {
         break;
       }
       case 2: {
-        logout(context, helper);
+        platform.invokeMethod('finish');
+        break;
       }
     }
   }