Merge branch '2.7' into 2.8

* 2.7:
  Fix PHP 7.1 related failures
  [VarDumper] Fix for 7.1

Author: fabpot

composer.json

@@ -33,7 +33,7 @@
         "symfony/security-acl": "~2.6|~3.0.0",
         "symfony/stopwatch": "~2.2|~3.0.0",
         "symfony/console": "~2.8|~3.0.0",
-        "symfony/var-dumper": "~2.6|~3.0.0",
+        "symfony/var-dumper": "~2.7.16|~2.8.9|~3.0.9",
         "symfony/expression-language": "~2.4|~3.0.0"
     },
     "suggest": {