检测用户是否开启推送

       if (IOS_MORE(8.0))
        {
            //iOS8 later
            if (UIUserNotificationTypeNone == [[[UIApplication sharedApplication] currentUserNotificationSettings] types])
            {
                [self presentNotificationDisableVC];
            }
        }
        else
        {
            //iOS7
            if([[UIApplication sharedApplication] enabledRemoteNotificationTypes] != (UIRemoteNotificationTypeSound | UIRemoteNotificationTypeBadge | UIRemoteNotificationTypeAlert))
            {
                [self presentNotificationDisableVC];
            }
        }