[Security][Acl] Issue #5787 : Added MutableAclProvider::deleteSecurityIdentity

Code style fix and documentation typo
Fix finder date constraints and tests
Consider KERNEL_DIR setting as relative to the PhpUnit XML file if it does not point to a directory (relative to the current cwd)
updated CHANGELOG for 2.4.0
updated VERSION for 2.4.0
bumped Symfony version to 2.4.1
encourage the running of coverage

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | no
| License       | MIT
| Doc PR        | no
Revert "encourage the running of coverage"

This reverts commit bb73852c95a5761d7d562fbc959367383b029264.
Changes the form icon in the toolbar to be pixel perfect.
[ExpressionLanguage] throw exception when parameters contain expressions
Refactor common code and reduce nesting
ErrorHandlerTest: restore_error_handler() on assertion failure
minor #9742 ErrorHandlerTest: restore_error_handler() on assertion failure (nicolas-grekas)

This PR was submitted for the 2.4-dev branch but it was merged into the 2.4 branch instead (closes #9742).

Discussion
----------

ErrorHandlerTest: restore_error_handler() on assertion failure

Before the patch, if any test fail in src/Symfony/Component/Debug/Tests/ErrorHandlerTest.php,
phpunit's error handler is not correctly restored.
When running a test batch, this breaks other tests that rely on its behavior (@expectedException PHPUnit_Framework_Error)

Commits
-------

a6ed37c ErrorHandlerTest: restore_error_handler() on assertion failure
[Debug] fixed tests
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
Merge branch '2.3' into 2.4

* 2.3:
  fixed CS
fixed CS
Merge branch '2.4'

* 2.4:
  fixed CS
  fixed CS
added ExpressionVoterTest