Signed-off-by: NJosé Valim <jose.valim@gmail.com>

Booting a new Rails application does not work after this commit [#5359 state:open]

This reverts commit 38a421b3.

Signed-off-by: NJosé Valim <jose.valim@gmail.com>

Including UrlFor in Redirecting and Head will warn usefully if a controller is wired up without a router included (and still support redirect_to "omg")

Remove duplicated url_for code and move methods shared between ActionMailer and ActionController up to AbstractController.

AC::Head now doesn't have an unfulfilled Rendering dependency, and instead works just fine standalone (which means that ConditionalGet also doesn't have a Rendering dependency)

This reverts commit 0cac68d3.

  * Removing the dependency on AD::Request and AD::Response
  * Moving the logic for the request and response object
    into a new module that is included by default.
  * Changing Renderer and Redirector to use self.headers,
    self.content_type, and self.status, which have very basic
    default implementations on AC::Http. When RackConvenience
    is included (which it is by default on AC::Base), the full
    Request/Response logic is used instead of the simple logic.