Deprecate IP spoofing settings that are directly on the controller in favor of configuring a middleware

Indicate that ActionController::Base.resource_action_separator is deprecated and only has an effect with the deprecated router DSL.

	* Refactored ActionPatch to use fullpath instead

Change AV formats so they can delegate to the controller. Now users (or plugins) can override details_for_render in their controllers and add appropriate additional details. Now if only they could *do* something with those details...

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 traces of SharedTestRoutes from user code; leave it as a standin for Rails.application.routes in Rails internal tests

	This attr_accessor can be set in a before filter or in the action itself.
    Overwriting default_url_options still works but will output a deprecation notice.

  * Add the Rack::Sendfile middleware
  * Make the header to use configurable via config.action_dispatch.x_sendfile_header (default to "X-Sendfile"). 
  * Add Railties tests to confirm that these work
  * Remove the :stream, :buffer_size, and :x_senfile default options to send_file
  * Change the log subscriber to always say "Sent file"
  * Add deprecation warnings for options that are now no-ops

Note that servers can configure this by setting X-Sendfile-Type. Hosting companies and those creating packages of servers specially designed for Rails applications are encouraged to specify this header so that this can work transparently.

Fix streaming by having it create a File object, which can be handled by Rack servers as appropriate