Add app/models/concerns and app/controllers/concerns to the default directory structure and load path

The conditional_layout? method is not for public use and doesn't
actually do what the documentation suggested it does. It's actually
used to determine whether or not to use the explicit layout definition
defined in a controller or use the implicit layout definition.

Also documentation was added for the action_has_layout? method which
acts as a master switch for disabling the layout for the current
action. This method was added so that action caching didn't depend
on accessing layout internals but is also used by third-parties,
most notably the [Hobo][1] application.

[1]: https://github.com/hobo/hobo

Add nodoc to AS::BasicObject [ci skip]

Add missing requires to core_ext/integer/time

DebugExceptions `File.join` => `File.expand_path`

Somehow this got lost in my PRs before. I'm going to re-check all the
guides to make sure this didn't happen again elsewhere.

Properly deprecate AS::BasicObject without breaking subclasses of it

Add `ActiveModel::Errors#add_on_present` method. Adds error messages to present attributes.

 Remove blank lines from generated Gemfile 

Introduced by 059bdc34

Conflicts:
	actionpack/lib/action_view/helpers/form_helper.rb
	railties/lib/rails/info_controller.rb

This reverts commit d1e70cb7.

This reverts commit 2f0311d7.

This reverts commit db9b619f.

This reverts commit e5f8b2be.

This reverts commit 6e72099a.

Reason: Feel that this isn't the right place.

The encoding scheme (e.g. ☠ -> "\u2620") was broken for characters
not in the Basic Multilingual Plane.  It is possible to escape them
for json using the weird encoding scheme of a twelve-character
sequence representing the UTF-16 surrogate pair (e.g. '𠜎' ->
"\u270e\u263a") but this wasn't properly handled in the escaping code.
Since raw UTF-8 is allowed in json, it was decided to simply pass
through the raw bytes rather than attempt to escape them.

Mysql2 doesn't support binds, which means no binds payload is set when
logging, so the logic to render binary data differently here doesn't work.

Introduced in 99d142a9.

Do not log the binding values for binary columns.

This reverts commit 6bdc0462.

This has been reverted because https://github.com/rails/rails/commit/8554537e48d6ed18ef08cb3ac0a9da96ac3c5cd6

This reverts commit ae68fc38, reversing
changes made to 0262a18c.

See here: https://github.com/rails/rails/pull/8499#issuecomment-11356417

They tend to be large and not very useful in the log.

Thread safety improvements

Fix for has_many_through counter_cache bug

Counter caches were not being updated properly when replacing
has_many_through relationships.

This commit fixes reported issue #7630 in which counter
caches were not being updated properly when replacing
has_many_through relationships

Removed :if / :unless conditions to fragment cache in favour of *cache_i...

cache_if(condition, option, &block) and cache_unless(condition, option, &block).

In the PR #8371 was introduced  conditional options :if and :unless in
the cache method.

    Example:

      <%= cache @model, if: some_condition(@model) do %>
        ...
      <%end%>

This is a good feature but *cache_if* and and *cache_unless*
are more concise and close to the standard of rails view helpers
(ex: link_to_if and link_to_unless).

    Example:

      <%= cache_if condition, @model do %>
      ...
      <%end%>

Remove all the old url helper methods when clear! is called on the
route set because it's possible that some routes have been removed.

This doesn't actually remove old url helper methods as they are
defined in a different module.

This reverts commit 96bcef94.

Conflicts:
	actionpack/CHANGELOG.md