[HttpFoundation] Documented public properties.
Merge branch '2.3' into 2.4

* 2.3:
  bumped Symfony version to 2.3.10
  updated VERSION for 2.3.9
  update CONTRIBUTORS for 2.3.9
  updated CHANGELOG for 2.3.9
  Add support SAPI cli-server
  Fix hardcoded listenerTag name in error message
  [HttpFoundation] Documented public properties.
  [Routing] add missing unit tests for Route and RouteCollection classes

Conflicts:
	src/Symfony/Component/HttpKernel/Kernel.php
	src/Symfony/Component/Routing/Tests/RouteCollectionTest.php