warning: assigned but unused variable - scope_called, path and strexp

No need to require to_param, it is already required in object/to_query.rb

[ci skip] add test for ActionModel::Conversion

Move tests for blank.rb under Object

Refactor determination of max updated timestamp

begin refactoring add_constraints by moving join keys

rm cached attributes

Add has_one? docs

Add test cases for #in? and #presence_in

Remove deprecation warning

Ensure `column_types` returns a type object, and not a column

Remove YAML serialization workaround for columns

The original patch that added this concept can be found
[here](https://web.archive.org/web/20090601022739/http://dev.rubyonrails.org/ticket/9767).
The current default behavior is to cache everything except serialized
columns, unless the user specified otherwise. If anyone were to specify
otherwise, many types would actually be completely broken. Still, the
method is left in place with a deprecation warning in case anyone is
actually still calling this method.

We are no longer including column objects in YAML serialization, thanks
to https://github.com/rails/rails/pull/15621

Follow up to #15636.

/cc @hundredwatt

Fix Apache Directives [ci skip]

Directives need to be placed on their own lines in order to work. Tested on: `Server version: Apache/2.2.22 (Ubuntu); Server built:   Mar 19 2014 21:11:15`

add missing changelog entry. refer [#16db90d1] [ci skip]

add_constraints is complicated and difficult to read. This is the
beginning of a long process of refactoring this code. First step:
moved the join keys out of AssociationScope and into reflection.

We then don't need to call `reflection` because now reflection is
`self`.

`foreign_key` must be named something else because reflection already has a
`foreign_key` method and when passed into `JoinKeys` it was getting the
wrong assignment. `reflection_foreign_key` seemed to be an appropriate name.
I also named `key` `reflection_key` to match `reflection_foreign_key`.

No need to decorate columns twice

[ci skip] Fix doc for javascript_helper

We never want result types to override column types, and
`decorate_columns` can only affect column types. No need to go through
the decoration multiple times, we can just exclude the column types from
the result types instead.

Correct Bundler link [ci skip]

[ci skip] Refine Action Mailer guide.

* Wrap 80 words if possible.
* Make attachment hash options more readable. (L239-L243)

  Before:

  ![screenshot 2014-06-11 02 59 54](https://cloud.githubusercontent.com/assets/1000669/3235432/a91d0464-f0d2-11e3-9e4a-6af2b2a83f1a.png)

   After:

  ![screenshot 2014-06-11 02 59 36](https://cloud.githubusercontent.com/assets/1000669/3235428/a47b28dc-f0d2-11e3-806c-cfaedd3f15df.png)

* L619 Wrap "location" in code: `"location"`.
* L628 Use actual section name.
* L697 Remove unnecessary `./` when refer to other guide.

remove deprecation call while initializing `ClassCache` object

fix error with long keys in ActiveSupport::Cache::FileStore