some fixes

Three main thing:

- removed the file app/bootstrap.php.cache which is auto generated by composer install/update

- phpunit added to require-dev in composer.json. So everyone can run the test suite with the same phpunit version (with ./bin/phpunit -c app)

- corrected all the phpcs errors inside the bundle, except the Tests folder

Thanks for the bundle! I'm posing like there's no tomorrow :cool: