Update composer, fix tests

Tests/Fixtures/app/config/default.yml

@@ -1,5 +1,4 @@
 framework:
-    charset:       UTF-8
     secret:        test
     csrf_protection:
         enabled: true
@@ -9,7 +8,6 @@ framework:
     test: ~
     default_locale: en
     session:
-        auto_start:     true
         storage_id:     session.storage.mock_file
     profiler:      { only_exceptions: false }
     templating:    { engines: ['twig'] }

composer.json

@@ -25,6 +25,7 @@
         "symfony/validator": "2.1.*",
         "symfony/yaml": "2.1.*"
     },
+    "minimum-stability": "dev",
     "autoload": {
         "psr-0": { "Nelmio\\ApiDocBundle": "" }
     },