[MonologBridge] Ignore empty context/extra by default in the ConsoleFormatter
[Form] Added "label_format" option
[Validator] Made it possible to store the cause of a constraint violation
[Intl] Integrated ICU data into Intl component
[Debug] expose object_handle
updated CHANGELOG for 2.3.20
update CONTRIBUTORS for 2.3.20
updated VERSION for 2.3.20
bumped Symfony version to 2.3.21
updated CHANGELOG for 2.5.5
updated VERSION for 2.5.5
bumped Symfony version to 2.5.6
[Validator] Update validators.zh_CN.xlf, fix translation error
minor #12070 [Validator] Update validators.zh_CN.xlf, fix translation error (michaeljayt)

This PR was submitted for the master branch but it was merged into the 2.3 branch instead (closes #12070).

Discussion
----------

[Validator] Update validators.zh_CN.xlf, fix translation error

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

Commits
-------

ab5aaab [Validator] Update validators.zh_CN.xlf, fix translation error
remove invalid tests

With #12046, the `getLocale()` method isn't overriden anymore by the
`Translator` from the FrameworkBundle, but the locale is set by the
new `TranslatorListener`. Therefore, the tests ensuring the old
behavior are removed.
[DebugBundle] fix dev dependencies
minor #12077 [DebugBundle] fix dev dependencies (xabbuh)

This PR was merged into the 2.6-dev branch.

Discussion
----------

[DebugBundle] fix dev dependencies

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

Commits
-------

3454e59 [DebugBundle] fix dev dependencies
minor #12076 [FrameworkBundle] remove invalid tests (xabbuh)

This PR was merged into the 2.6-dev branch.

Discussion
----------

[FrameworkBundle] remove invalid tests

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

With #12046, the `getLocale()` method isn't overriden anymore by the `Translator` from the FrameworkBundle, but the locale is set by the new `TranslatorListener`. Therefore, the tests ensuring the old behavior are removed.

Commits
-------

80d52c7 remove invalid tests
[EventDispatcher] fix doc bloc on EventDispatcherInterface
[HttpKernel] fix composer.json