[Routing] add support for path-relative and scheme-relative URL generation
[Routing] added tests for generating relative paths and network paths
[Routing] made reference type fully BC and improved phpdoc considerably
fix phpdoc of UrlGeneratorInterface that missed some exceptions and improve language of exception message
[Form] Prevent trigger of E_USER_DEPRECATED for new API
[HttpFoundation] Update docblock for non-working method
updated CHANGELOG for 2.0.21
updated VERSION for 2.0.21
bumped Symfony version to 2.0.21-DEV
add preferred_query option to ModelType

This enables the ModelChoiceList to use 'preferred_choices' of the parent ChoiceType.
use preferred_choices in favor of preferred_query
HttpUtils must handle RequestMatcher too
Hebrew validator - added some missing validator keys
merged branch excelwebzone/validator (PR #6476)

This PR was merged into the master branch.

Commits
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b32c37d Hebrew validator - added some missing validator keys

Discussion
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Hebrew validator - added some missing validator keys
[Validator] Card validation - Italian translations
merged branch hpatoio/master (PR #6477)

This PR was merged into the master branch.

Commits
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0fa7378 [Validator] Card validation - Italian translations

Discussion
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[Validator] Card validation - Italian translations

Bug fix: no
Feature addition: no
Backwards compatibility break: no
Symfony2 tests pass: no
[Routing] Used static to call constant in XmlFileLoader
[HttpKernel] changed the value of route to the pattern when it is a Route object in the data collector

This allows to have a meaningful information in the WDT when the route
in the Request is not the route name but the route object (like in
Drupal for instance).
[HttpKernel] fixed bundles var initialization
Fixed php doc of GenericEvent::__construct