* 2.6:
[EventDispatcher] make listeners removable from an executed listener
[HttpFoundation] Fix volatile MongoDbSessionHandlerTest::testRead()
Fixed compatibility with PHP7 and up by introducing new constraints (IsNull, IsTrue, IsFalse) and related validators (IsNullValidator, IsTrueValidator, IsFalseValidator)
Conflicts:
src/Symfony/Component/Validator/Constraints/FalseValidator.php
src/Symfony/Component/Validator/Constraints/NullValidator.php
src/Symfony/Component/Validator/Constraints/TrueValidator.php
src/Symfony/Component/Validator/Tests/Constraints/LegacyFalseValidator2Dot4ApiTest.php
src/Symfony/Component/Validator/Tests/Constraints/LegacyFalseValidatorLegacyApiTest.php
src/Symfony/Component/Validator/Tests/Constraints/LegacyNullValidator2Dot4ApiTest.php
src/Symfony/Component/Validator/Tests/Constraints/LegacyNullValidatorLegacyApiTest.php
src/Symfony/Component/Validator/Tests/Constraints/LegacyTrueValidator2Dot4ApiTest.php
src/Symfony/Component/Validator/Tests/Constraints/LegacyTrueValidatorLegacyApiTest.php
* 2.3:
Fixed compatibility with PHP7 and up by introducing new constraints (IsNull, IsTrue, IsFalse) and related validators (IsNullValidator, IsTrueValidator, IsFalseValidator)
Conflicts:
src/Symfony/Component/Form/composer.json
src/Symfony/Component/Validator/CHANGELOG.md
src/Symfony/Component/Validator/Constraints/FalseValidator.php
src/Symfony/Component/Validator/Constraints/NullValidator.php
src/Symfony/Component/Validator/Constraints/TrueValidator.php
src/Symfony/Component/Validator/Tests/Constraints/IsFalseValidatorTest.php
src/Symfony/Component/Validator/Tests/Constraints/IsNullValidatorTest.php
src/Symfony/Component/Validator/Tests/Constraints/IsTrueValidatorTest.php