Revert composer.json to use 2.1 versions again instead of `dev-master`.

composer.json

@@ -19,21 +19,21 @@
     "require": {
         "php": ">=5.3.2",
         "pimple/pimple": "dev-master",
-        "symfony/browser-kit": "dev-master",
-        "symfony/class-loader": "dev-master",
-        "symfony/css-selector": "dev-master",
-        "symfony/dom-crawler": "dev-master",
-        "symfony/event-dispatcher": "dev-master",
-        "symfony/http-foundation": "dev-master",
-        "symfony/http-kernel": "dev-master",
-        "symfony/routing": "dev-master"
+        "symfony/browser-kit": "2.1.*",
+        "symfony/class-loader": "2.1.*",
+        "symfony/css-selector": "2.1.*",
+        "symfony/dom-crawler": "2.1.*",
+        "symfony/event-dispatcher": "2.1.*",
+        "symfony/http-foundation": "2.1.*",
+        "symfony/http-kernel": "2.1.*",
+        "symfony/routing": "2.1.*"
     },
     "suggest": {
-        "symfony/form": "dev-master",
+        "symfony/form": "2.1.*",
         "monolog/monolog": ">=1.0.0",
-        "symfony/translation": "dev-master",
-        "symfony/twig-bridge": "dev-master",
-        "symfony/validator": "dev-master",
+        "symfony/translation": "2.1.*",
+        "symfony/twig-bridge": "2.1.*",
+        "symfony/validator": "2.1.*",
         "twig/twig": ">=1.2.0"
     },
     "autoload": {