remove scope_chain delegate
remove chain delegate
remove railties changes. fixes #14054

Squashed commit of the following:

commit 96991e8e919edfb20cc4120bca4e36ed51175d57
Author: Aaron Patterson <aaron.patterson@gmail.com>
Date:   Fri Feb 14 11:29:24 2014 -0800

    Revert "gems can be added or skipped from the template"

    This reverts commit 8beb42cfbc41753ae4dbb91e16abcd1fb7d00356.

    Conflicts:
    	railties/lib/rails/generators/rails/app/app_generator.rb
    	railties/test/generators/app_generator_test.rb

commit 35599c0e657245ef14ac0f28c9189ad16acf40e6
Author: Aaron Patterson <aaron.patterson@gmail.com>
Date:   Fri Feb 14 11:26:53 2014 -0800

    Revert "oops, template replay needs to happen after bundle. :orz:"

    This reverts commit 9104702be61253f9448ca070a22fc86bb4299555.

    Conflicts:
    	railties/lib/rails/generators/rails/app/app_generator.rb

commit f519c3902c313db8e906a49251c91643b8e6499e
Author: Aaron Patterson <aaron.patterson@gmail.com>
Date:   Fri Feb 14 11:25:51 2014 -0800

    Revert "only ask for these ivars if the target responds to them"

    This reverts commit 656d412546cd97d5660c634c2a41c799d3f9e211.

commit aa524a9428e3e4c45fe221f10a66a08efb827ab5
Author: Aaron Patterson <aaron.patterson@gmail.com>
Date:   Fri Feb 14 11:25:39 2014 -0800

    Revert "refactor generator tests to use block form of Tempfile"

    This reverts commit 65251820ef0ab7f3cffb38130de3dd41af8d72be.

commit 7d3740549fa4dfa62e3761f8d4bc6d6d441256e7
Author: Aaron Patterson <aaron.patterson@gmail.com>
Date:   Fri Feb 14 11:25:25 2014 -0800

    Revert "add a more restricted codepath for templates fixes #13390"

    This reverts commit 2875b4a66e38e4333da887a4afbed33358999298.

commit 525df0af1001918986cdfce59539fd2d52c4f32c
Author: Aaron Patterson <aaron.patterson@gmail.com>
Date:   Fri Feb 14 11:25:11 2014 -0800

    Revert "add a send so `apply` can be called.  Fixes #13510"

    This reverts commit c5034d60dba0cd31a6a8c612ee35d63b8127793a.
Introduce `render :body` for render raw content

This is an option for sending a raw content back to browser. Note that
this rendering option will unset the default content type and does not
include "Content-Type" header back in the response.

You should only use this option if you are expecting the "Content-Type"
header to not be set. More information on "Content-Type" header can be
found on RFC 2616, section 7.2.1.

Please see #12374 for more detail.
Update hash format for render_text_test
Introduce `render :plain` for render plain text

This is as an option for render content with a content type of
`text/plain`. This is a preferred option if you are planning to render a
plain text content.

Please see #12374 for more detail.
Introduce `render :html` for render HTML string

This is an option for render HTML content with a content type of
`text/html`. This rendering option calls `ERB::Util.html_escape`
internally to escape unsafe HTML string, so you will have to mark your
string as html safe if you have any HTML tag in it.

Please see #12374 for more detail.
Fix a fragile test on `action_view/render`

This test were assuming that the list of render options will always be
the same. Fixing that so this doesn't break when we add/remove render
option in the future.
Cleanup `ActionController::Rendering`
Update guides for new rendering options

* Introduces `:plain`, `:html`, `:body` render option.
* Update guide to use `render :plain` instead of `render :text`.
Add missing CHANGELOG entry to Action View
Add `#no_content_type` attribute to `AD::Response`

Setting this attribute to `true` will remove the content type header
from the request. This is use in `render :body` feature.