Bump the phpunit dependency and add some symfony components.

composer.json

@@ -41,10 +41,14 @@
         "whitehat101/apr1-md5": "~1.0",
         "twig/twig": "~1.0",
         "gettext/gettext": "^4.6",
-        "jaimeperez/twig-configurable-i18n": "^1.2"
+        "jaimeperez/twig-configurable-i18n": "^1.2",
+        "symfony/routing": "^3.4",
+        "symfony/http-foundation": "^3.4",
+        "symfony/config": "^3.4",
+        "symfony/http-kernel": "^3.4"
     },
     "require-dev": {
-        "phpunit/phpunit": "~4.8.35",
+        "phpunit/phpunit": "~5.7",
         "mikey179/vfsStream": "~1.6",
         "friendsofphp/php-cs-fixer": "^2.2"
     },