[Translator] coding style
[Translator] fix MessageCatalogueInterface::getFallbackCatalogue that can return null

also use inheritdoc for the implementation
[Translator] mention that the message id may also be an object that can be cast to string in TranslatorInterface and fix the IdentityTranslator that did not respect this
[Translator] fix phpdoc of MessageCatalogueInterface::add and ::replace
[Translator] optimized adding of resources and saving a call to array_unique
[Translator] fix typecast in transChoice
[Translator] fix metadata

- fix '0' problem
- only access metadata when implementing interface
- refactor code
- clarify phpdoc
[Finder] Unified tests
fixed CS
Revert "merged branch jfsimon/issue-6749 (PR #7220)"

This reverts commit f52120bdd33bcc83157fc55ee088a564c727fa59, reversing
changes made to 66c2be30d06bf8c9bee9e07aa57be245763c2478.
[Console] added string input test
[Console] fixed StringInput binding
[DomCrawler] Fix relative path handling in links

Added relative path canonicalization according to RFC 3986, section 5.2.4
[ClassLoader] made DebugClassLoader idempotent
[ClassLoader] tweaked test
[Routing] make xml loader more tolerant

schemes and methods may also be delimited by whitespace, comma or pipe.
this eases migration as now schemes="GET|POST" also works
[Routing] unify and fix the loader tests
[Routing] trigger deprecation warning for deprecated features that will be removed in 2.3
adjusted tests to not use RouteCollection::getPrefix
adjust tests to no use addPrefix with options