Make ArgumentError message more consistent in nested attributes

This reverts commit 9669f6f7.

This breaks Sam Ruby's tests for some reason.  Revert until we figure it
out.

* master:
  Add documentation for inheritance_column method
  Use ArgumentError vs. RuntimeError, which is more precise.
  CSV fixtures aren't supported by default anymore, update generated test_helper.rb to reflect that
  fix quoting for ActiveSupport::Duration instances
  Add few information on the field types
  Add the options method to action_controller testcase.

Add documentation for inheritance_column method [ci skip]

Add the options method to action_controller testcase.

Add few information on the field types

fix quoting for ActiveSupport::Duration instances

Use ArgumentError vs. RuntimeError, which is more precise

CSV fixtures aren't supported by default anymore, update generated test_helper.rb to reflect that

This patch fixes quoting for ActiveSupport::Duration instances:

    # before
    >> ActiveRecord::Base.connection.quote 30.minutes
    => "'--- 1800\n...\n'"

    # after
    >> ActiveRecord::Base.connection.quote 30.minutes
    => "1800"

Also, adds a test for type casting ActiveSupport::Duration instances.

Related to #1119.

* master:
  activesupport gem dependencies should reflect the versions we actually use
  fix link and add activeresource link in release notes page [ci skip]
  Update 4.0 Release Notes
  Kill not used constant since removal of runner method

fix link and add activeresource link in release notes page [ci skip]

Signed-off-by: NFrançois de Metz <francois@stormz.me>

Related with 17d2115e

instead of deleting keys on every instantiation, create defaults we
actually use.  eventually we can pass an environment in to the request,
and create a new req / res object on each call.

Runner method was removed in ada571bf.

merging cookies is responsibility of the test runner

For some reason, this special logic is only supposed to be executed on
the second request.  For now, we'll extend on recycle, but we should
figure out why this functionality can't be run on every request

Try to avoid making the controller mutate itself so that we can
eventually make the response async

Mocha is already required by AS::TestCase, so remove the duplicate
requires.

remove test/dummy from gitignore when "plugin new -T"

Closes #6920