Merge branch '2.2' into 2.3

* 2.2:
  Remove +x mode on file
  updated doc links
  updated VENDORS for 2.1.10

Conflicts:
	README.md
updated versions in the README file
Fixed accidentally removed status code in app/check.php
merged branch maxromanovsky/app-config-status-code-fix (PR #553)

This PR was submitted for the master branch but it was merged into the 2.3 branch instead (closes #553).

Discussion
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Fixed accidentally removed status code in app/check.php

Commits
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bbf5680 Fixed accidentally removed status code in app/check.php
updated VENDORS for 2.3.0
Created the project basic documentation
Removed Standard's own documentation basic files
Added link to symfony standard edition
Renamed the composer package
Removed the requirement test
Removed Swiftmailer dependance and configuration
Incremented the minimum PHP version to 5.3.17
Used twig without extensions
Used empty (blank) favicons
Removed the changelogs
Removed AcmeDemoBundle
Intercepted redirection in development environment
Added the differences with the standard edition
Fixed composer.json extra commas
Removed broken link to deleted version file