Update to Symfony 4.1 #149 (#160)

* updated to Symfony 4.1 #149
* updated to phpunit 7 #149
* downgrade ocramius/proxy-manager for PHP 7.1 compatibility #149
* fixed symfony deprecations #149
* replaced AdvancedUserInterface with custom user checker
* code sniffer fixes

src/Entity/User.php

@@ -25,7 +25,7 @@ use Symfony\Bridge\Doctrine\Validator\Constraints\UniqueEntity;
  * @UniqueEntity("username")
  * @UniqueEntity("email")
  */
-class User implements UserInterface, AdvancedUserInterface
+class User implements UserInterface
 {
     const ROLE_CUSTOMER = 'ROLE_CUSTOMER';
     const ROLE_USER = 'ROLE_USER';
@@ -405,30 +405,6 @@ class User implements UserInterface, AdvancedUserInterface
         return $this;
     }
 
-    /**
-     * @inheritdoc
-     */
-    public function isAccountNonExpired()
-    {
-        return true;
-    }
-
-    /**
-     * @inheritdoc
-     */
-    public function isAccountNonLocked()
-    {
-        return true;
-    }
-
-    /**
-     * @inheritdoc
-     */
-    public function isCredentialsNonExpired()
-    {
-        return true;
-    }
-
     /**
      * @return bool
      */