refactor the naming within plugin new generator

Having a method called `full?`, which checks on :full and :mountable
is very confusing. I renamed `full?` to `engine?` and created a `full?`
method that only checks the `:full` option
change spy of  after invoked controller action. because ruby-2.0.0 waned unused variables
Eager loading made to use relation's in_clause_length instead of host's one (fixes #8474)
Test nested fields with AssociationProxy mockup & fix AssociationProxy support in form helper
Document JoinTable migration generator
Update documentation for yml usage

Update documentation for yml usage against https://github.com/rails/rails/issues/8612
Update guides/source/layouts_and_rendering.md

Removed first slash. The subdirectory will nto be found with slash befor it.
Fix missing ending newline in db structure dump:

  When dumping database structure with `rake db:structure:dump` and
using migrations, the resulting file will not end with a newline char.
Although it's not mandatory, it breaks a lot of simple use cases with
programs like cat, more, grep, etc.

  This changes use `puts' instead of `<<' to append migration versions
data to the dump and also split the line where this is happening as it
was a bit long.
Improve secret_token deprecation message
Merge pull request #8651 from tjouan/activerecord-structure_dump-ending_nl

Fix missing ending newline in db structure dump:
Point to guides.rubyonrails.org instead of edgeguides.rubyonrails.org
Revert "Rails 4.0 is going to depend on Rack 1.5.x so let's test against Rack master"

This reverts commit fba97c9620e709f0449ea9f3240b9e5174f72e1e.
fixed inconsistent `require 'test_helper'` in testing guide
Merge pull request #8546 from hsbt/fix-testcase-strict-warning

fix testcase: ruby-2.0.0 warned unused variables
Define [], []=, permanent, signed and encrypted as the only allowed methods for the non Raw Cookie classes
Update guides/source/rails_on_rack.md

Rack::Lock actually sets rack.multithread to `false`, not `true`.

Presumably because once inside the mutex, the app can function as if it were single threaded.
charset should not be appended for `head` responses

      1) Failure:
    test_head_created_with_image_png_content_type(RenderTest) [test/controller/render_test.rb:1238]:
    Expected: "image/png"
      Actual: "image/png; charset=utf-8"
Merge pull request #8662 from senny/8661_should_not_append_charset_if_already_present

Charset should not be appended to image/* type
Fix usage of lambda as a Rack endpoint

The response body needs to respond_to? :each.
Revert "minitest provides "it" and "describe""

This reverts commit 22bc12ec374b8bdeb3818ca0a3eb787dd3ce39d8.

REASON: We will remove the MiniTest::Spec from Rails and we need these
methods again

Conflicts:
	activesupport/lib/active_support/test_case.rb