make scheme and method requirements first-class citizen in Route
added scheme and method setter in RouteCollection
made schemes and methods available in YamlFileLoader
made schemes and methods available in XmlFileLoader

it uses an attribute list instead of multiple scheme/method elements that I also experimented with
[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
fix double-decoding in the routing system
Fixed failing test
[Locale] fixed a test
Making it easier to grab the PR template.
merged branch drak/contributing (PR #6378)

This PR was merged into the 2.0 branch.

Commits
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df0623f Making it easier to grab the PR template.

Discussion
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Making it easier to grab the PR template.
Fix #6374 move FormBuilderInterface from Tests to Test
Move DeprecationErrorHandler to Test folder so it's not removed when building the zip file
[TwigBridge] added an extension for the HttpKernel component
[TwigBundle] added the HttpKernel extension to the default Twig loaded extensions
[WebProfilerBundle] replaced usage of the render tag by the render function (to decouple the bundle from TwigBundle)
[WebProfilerBundle] fixed exception panel when no exception is thrown
[WebProfilerBundle] replaced yaml_dump by json_encode to make the Web Profiler independent from the YAML component