Changes in old branches needed to be manually synched in CHANGELOGs of newer ones.
This has proven to be brittle, sometimes one just forgets this manual step.
With this commit we switch to CHANGELOGs per branch. When a new major version is
cut from master, the CHANGELOGs in master start being blank.

A link to the CHANGELOG of the previous branch allows anyone interested to
follow the history.

Nowadays circular autoloads do not work, but the user gets a NameError
that says some constant is undefined. That's puzzling, because he is
normally trying to autoload a constant he knows can be autoloaded.
With this check we can give a better error message.

Fix method redefined warnings.

Fixes warnings when executing rake test in ActionMailer. 

Fixes warnings when executing rake test in ActionMailer. Related to 582a7f45

Tiny fixes in railties/test/application.

loaded stores file names without the .rb extension, but search_for_file
returns file names with the extension.

The solution is hackish, but this file needs a revamp.

removed :  warning: `*' interpreted as argument prefix

Memcached to dalli for actionpack test.

Change generators controller help from singular to plural example.

When running `rails generate controller --help` an example
with creating a (singular) "CreditCard" controller is
shown. The convention is to generate controllers with plural
names though.

fix order dependent test in AR::BasicsTest

This branch contains set of changes that will allow to extract Action
View out of Action Pack in the future. This work will be probably done
after Rails 4.0 release, because of a few deprecations that were done
to make decoupling possible.

Methods provided by RecordIdentifier are not widely used in controllers
nowadays as they're view specific (this is probably a legacy left after
RJS rendering directly in controllers). However if people still need to
use it, it's trivial to include ActionView::RecordIdentifier by
themselves.

We extend it with self, but the methods were not working properly were
used directly on module.

When module is extended ActiveSupport::Concern, include calls are lazily
loaded, so there is no need to wrap it with included hook.

AV::Template::Types is a small abstraction to allow to specify template types
that can be used in ActionView. When Action Pack is loaded it's replaced with
Mime::Type.

ActionDispatch::Routing::UrlFor was always required in UrlHelpers. This
was changed by splitting previous implementation of UrlHelper into 2
modules: ActionView::Helpers::UrlHelper and
ActionView::Routing::UrlHelper. The former one keeps only basic
implementation of url_for. The latter adds features that allow to use
routes and is only required when url_helpers or mounted_helpers are
required.

default_formats array is used by LookupContext in order to allow
rendering templates when :formats option is not passed. Previously it
was always set to Mime::SET, which created dependency on Action Pack. In
order to remove this dependency, Mime::SET is used only if
ActionController is loaded.

Action View should not be responsible for translating mime types. Any
translation that's needed should be handled at controller level.

Automatically handling mime types for things other than :rss and :atom
is not functionality that justifies dependency on Mime::Type from
actionpack.

I've talked to José Valim, who added this comment, and there is no need
to remove old API. It's good to have a simple way to instantiate
ActionView::Base, by just passing view paths as a first argument,
instead of constructing LookupContext and then the Renderer.

[ci skip]

We can use another way to instantiate ActionView::Base, by passing
renderer as a first option. Thanks to that we can just pass prefixes to
LookupContext instead stubbing them on the controller. This is also good,
because that kind of API is used in Rails code.

This is another step in moving Action View's dependencies in Action Pack
to Action View itself. Also, HtmlScanner seems to be better suited for
views rather than controllers.

It's just a duplicate of ActionController::ModelNaming. These are just a
simple helpers for decoupling Active Model, so it does not make sense to
extract it to Active Support, but the point is to decouple also Action
View and Action Pack

Since it's more about DOM classes and ids it belongs to Action View
better. What's more, it's more convenient to make it part of Action View
to follow the rule that Action Pack can depend on Action View, but not
the other way round.

Since Action View should not depend on actionpack, it's best to delegate
invalid_asset_host! to controller and just rely on such simple contract
instead of raising ActionController::RoutingError directly.

ensures that the test repairs the validation setup

This test https://github.com/rails/rails/blob/master/activerecord/test/cases/base_test.rb#L381
is failing because is not setting `CreditCard.pluralize_table_name` to `false`.

In this case, i prefer to change to another model that is not in the `GUESSED_CLASSES`
array.