Merge pull request #3558 from GrahamForks/deps

[5.2] Added two symfony deps to require-dev

composer.json

@@ -11,7 +11,9 @@
     "require-dev": {
         "fzaninotto/faker": "~1.4",
         "mockery/mockery": "0.9.*",
-        "phpunit/phpunit": "~4.0"
+        "phpunit/phpunit": "~4.0",
+        "symfony/css-selector": "2.8.*|3.0.*",
+        "symfony/dom-crawler": "2.8.*|3.0.*"
     },
     "autoload": {
         "classmap": [