[HttpKernel] use static late binding when dumping out container
updated VERSION for 2.4.0
bumped Symfony version to 2.4.1
minor #9678 [HttpKernel] use static late binding when dumping out container (tgabi333)

This PR was submitted for the 2.2 branch but it was merged into the 2.3 branch instead (closes #9678).

Discussion
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[HttpKernel] use static late binding when dumping out container

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | no?
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets |  #9649
| License       | MIT
| Doc PR        |

This PR gives the ability to override the stripComments method in descendants (and to disable the memory-eater container whitespace stripping)

Commits
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2e241cc [HttpKernel] use static late binding when dumping out container
Merge branch '2.3' into 2.4

* 2.3:
  Fixed typo
  [validator] throw an exception if isn't an instance of ConstraintValidatorInterface.
  Reset the box model to content-box in the web debug toolbar
  [FrameworkBundle] Allowed "0" as a checkbox value in the php template.
  raising delta on stopwatch as travis really breaks with less than 35
  Switched to correct gender of "Token"
  fixed typos in several translations
  [HttpKernel] use static late binding when dumping out container
Merge branch '2.4'

* 2.4:
  [Debug] fixed tests
  ErrorHandlerTest: restore_error_handler() on assertion failure
  Fixed typo
  [validator] throw an exception if isn't an instance of ConstraintValidatorInterface.
  Reset the box model to content-box in the web debug toolbar
  [FrameworkBundle] Allowed "0" as a checkbox value in the php template.
  raising delta on stopwatch as travis really breaks with less than 35
  Switched to correct gender of "Token"
  bumped Symfony version to 2.4.1
  updated VERSION for 2.4.0
  updated CHANGELOG for 2.4.0
  fixed typos in several translations
  [HttpKernel] use static late binding when dumping out container

Conflicts:
	src/Symfony/Component/HttpKernel/Kernel.php