Merge branch '2.3' into 2.4

* 2.3:
  fixed various inconsistencies
  reduced recursion when building DumperPrefixCollection
  renamed variables - making next change more readable
  removing dead code.
  [DomCrawler] Fixed filterXPath() chaining
  [DomCrawler] Fixed incorrect handling of image inputs

Conflicts:
	src/Symfony/Component/DomCrawler/Crawler.php
	src/Symfony/Component/EventDispatcher/Tests/EventDispatcherTest.php
	src/Symfony/Component/Form/Extension/DependencyInjection/DependencyInjectionExtension.php
	src/Symfony/Component/Serializer/Tests/Normalizer/CustomNormalizerTest.php
	src/Symfony/Component/Templating/Tests/Loader/CacheLoaderTest.php
	src/Symfony/Component/Templating/Tests/Loader/LoaderTest.php
Merge branch '2.4'

* 2.4:
  fixed various inconsistencies
  reduced recursion when building DumperPrefixCollection
  renamed variables - making next change more readable
  removing dead code.
  [ExpressionLanguage] added some tests for the built-in constant() function
  [ExpressionLanguage] added some documentation about functions
  [DomCrawler] Fixed filterXPath() chaining
  [DomCrawler] Fixed incorrect handling of image inputs