[composer] re-add css-selector, adjust versioning syntax

composer.json

@@ -19,11 +19,12 @@
     "require": {
         "php": ">=5.3.2",
         "pimple": ">=1.0.0",
-        "symfony/browser-kit": "2.0.*",
-        "symfony/dom-crawler": "2.0.*",
-        "symfony/event-dispatcher": "2.0.*",
-        "symfony/http-foundation": "2.0.*",
-        "symfony/http-kernel": "2.0.*",
-        "symfony/routing": "2.0.*"
+        "symfony/browser-kit": ">=2.0",
+        "symfony/css-selector": ">=2.0",
+        "symfony/dom-crawler": ">=2.0",
+        "symfony/event-dispatcher": ">=2.0",
+        "symfony/http-foundation": ">=2.0",
+        "symfony/http-kernel": ">=2.0",
+        "symfony/routing": ">=2.0"
     }
 }