Methods raising ActiveRecord::RecordNotFound were returning 404 on first request and 200 OK with blank body on subsequent requests.

[#2533 state:committed]
Signed-off-by: NJeremy Kemper <jeremy@bitsweat.net>

Deprecate template, session, assigns, and layout accessors on response object. Instead access them through the controller instance. This mainly affects functional test assertions.

  ActionView::Template is now completely independent from template
  storage, which allows different back ends such as the database.
  ActionView::Template's only responsibility is to take in the
  template source (passed in from ActionView::Path), compile it,
  and render it.

Now that we have a separate internal rails_to_json, use a separate circular reference stack instead of sticking it in the options hash

Inherit TestSession from Session::AbstractStore and add indifferent access to Session::AbstractStore.