So that a customized HTTPServer subclass can use it's own
Request/Response classes.

To apply the override, make a subclass of WEBrick::HTTPServer
and override the
`create_request_and_response(with_webrick_config)` method. The
method should return an Array of [request, response].

To check whether the Server supports this method (i.e. when
using older versions of WEBrick when needing this
functionality), you can ask the server if it responds to the
method

    server.respond_to?(:create_request_and_response)

This is backportable.

[ruby-core:69604] [Feature #11266]

From: Julik Tarkhanov <me@julik.nl>

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@66452 b2dd03c8-39d4-4d8f-98ff-823fe69b080e