Updating newline fix to maintain existing linebreaks and indentation and...

middlewares should have configurable logger

This implements the ActiveModel::Serializer object. Includes code, tests, generators and guides.

From José and Yehuda with love.

Conflicts:
	railties/CHANGELOG.md

Added tests for #3751

make ActiveModel::Name fail gracefully with anonymous classes

The following constants were renamed:

  ActiveModel::Serialization     => ActiveModel::Serializable
  ActiveModel::Serializers::JSON => ActiveModel::Serializable::JSON
  ActiveModel::Serializers::Xml  => ActiveModel::Serializable::XML

The main motivation for such a change is that `ActiveModel::Serializers::JSON`
was not actually a serializer, but a module that when included allows the target to be serializable to JSON.

With such changes, we were able to clean up the namespace to add true serializers as the ArraySerializer.

configuration option to always write cookie

code stats calculation

Warnings removed. (ambiguous first argument)

Issues/3737 AS::Cache.expand_cache_key

Fix #3728 Remove unreachable code, and add additional testcases.

`nil` and `false` both expand to `""` (empty string), while `true` expands to
`"true"`; `false` should expand to `"false"`

`cache_key` method is never called when the argument is a 1-element array
with something that responds to `cache_key`

improved code stats calculation, check on multiline comments and rewrite regexps according to a class naming convention

Fix inconsistencies with Time{WithZone}#{hash,eql?}

stylesheet_tag default's media is "screen"