Document changes in #7968
Merge pull request #9317 from balexand/patch-1

Document changes from #7968 in Upgrading Guide
Add headings to rake routes table
Merge pull request #9318 from steveklabnik/router_headings

Add headings to rake routes table
Add message when you have no routes defined.

Print a message in both `rake routes` and at GET "/rails/info/routes"
that lets you know you have no routes defined, as well as linking to the
Rails Guide on the topic.
Merge pull request #9316 from steveklabnik/no_routes

Print message on stderr when no routes are defined.
use strip_heredoc to keep indentation consistent.

Thanks @sikachu. :heart:
Use strip_heredoc in the tests as well.

Thanks @sikachu. :sweat_smile:
editorial tweaks
Duck typing is hard. Add header to HtmlTableFormatter.

Somehow I missed this method, which was then throwing an error
when viewing routes as HTML.

Make @rubys happy: ✔
Revert "Deprecate the `eager_load_paths` configuration"

Because of the possibility of lib being unintentionally eager loaded
it's been agreed that we'll leave autoload paths and eager load paths
separate for Rails 4.0.

This reverts commit 0757b3388ffe4f44b60de950d40e18ef05055931.

Conflicts:
	railties/CHANGELOG.md
Don't unhook autoloading in production

Whilst autoloading is known to be not threadsafe, leaving it in place
is a softer solution than failing hard when an application is deployed.

Many older applications will have paths added to `autoload_paths` and
ideally these should be eagerly loaded to be threadsafe. However one
of these paths is quite often lib which could lead to unintended
consequences due to the 'junk drawer' nature of this directory.

Developers should refrain from adding paths to `autoload_paths` or
`eager_load_paths` and use custom folders inside app for code that
needs to be eagerly loaded and use `require` or `require_dependency`
to explicitly load code from other locations.
Remove config.autoload_paths from config/application.rb

Most application developers shouldn't be adding paths to
`config.autoload_paths` as it won't be eagerly loaded so
remove it from the generated config/application.rb file.

If a developer does want to autoload from paths outside of the app
directory then they should add the path to `config.eager_load_paths`
as these paths are also autoloaded as well.
Require AS deps in ActionDispatch::Http::URL

Allows us to use url_for and friends in isolation.
Merge pull request #9321 from mfilej/action-dispatch-http-url-requires

Require ActiveSupport dependencies in ActionDispatch::Http::URL
Add missing require to routes inspector
Fix AP tests related to routes inspector output and the new column titles
Fix rake routes output in railties test
InvalidMessage is in ActiveSupport::MessageEncryptor namespace

Closes #9302