Merge branch '2.7' into 2.8

* 2.7:
  Fix one dependency requirement

Conflicts:
	src/Symfony/Component/Serializer/composer.json

Author: nicolas-grekas

composer.json

@@ -20,7 +20,7 @@
     },
     "require-dev": {
         "symfony/phpunit-bridge": "~2.7|~3.0.0",
-        "symfony/yaml": "~2.0|~3.0.0",
+        "symfony/yaml": "~2.0,>=2.0.5|~3.0.0",
         "symfony/config": "~2.2|~3.0.0",
         "symfony/property-access": "~2.3|~3.0.0",
         "doctrine/annotations": "~1.0",