Merge branch '3.1'

* 3.1:
  [CS] Respect PSR2 4.2
  [Form] fix `empty_data` option in expanded `ChoiceType`
  [Console] removed unneeded private methods
  updated Http-Kernel dependency
  [Security] [Guard] Improve comment with working example
  sync min email validator version
  [TwigBridge] Fix inconsistency in LintCommand help
  explicitly forbid e-mail validator 2.0 or higher
  Fixed SymfonyQuestionHelper multi-choice with defaults
  [DoctrineBridge] Don't use object IDs in DoctrineChoiceLoader when passing a value closure
  Differentiate between the first time a progress bar is displayed and subsequent times
  finished previous commit
  No more exception for malformed input name
  fix post_max_size_message translation
  [Process] Fix pipes cleaning on Windows
  Avoid phpunit 5.4 warnings on getMock
  [Form] Add exception to FormRenderer about non-unique block names
  [FrameworkBundle] templating can be fully disabled
  [Form] Consider a violation even if the form is not submitted

Author: fabpot

composer.json

@@ -17,7 +17,7 @@
     ],
     "require": {
         "php": ">=5.5.9",
-        "symfony/http-kernel": "~2.8|~3.0",
+        "symfony/http-kernel": "~3.1",
         "symfony/polyfill-php70": "~1.0",
         "symfony/routing": "~2.8|~3.0",
         "symfony/twig-bridge": "~2.8|~3.0"