Added status code to app/check.php
merged branch maxromanovsky/app-config-status-code (PR #516)

This PR was squashed before being merged into the master branch (closes #516).

Discussion
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Added status code to app/check.php

This change could be useful in build scripts. `app/check.php` could be executed in order to check that build environment is sane.
Changes:
1. Added status code to `app/check.php`
1. Updated `README.md`

Commits
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ded4360 Added status code to app/check.php
tweaked previous merge
Merge pull request #4 from symfony/master

Merge symfony/standard with Lexance/symfony-multidomain [master]