Last week we released version 1.2.0 of our Magento 2 Force Frontend Customer Login module which is compatible now with the latest 2.1 version of Magento. You can download the release on Github or require it via Composer:
composer.phar require bitexpert/magento2-force-customer-login
If you find a bug or in case you have a feature request please use the GitHub issue tracker to report the issue.