For future reference, this is the regex I used: ^\s*#\s*\n(?!\s*#). Replace
with the first match, and voilà! Note that the regex matches a little bit too
much, so you probably want to `git add -i .` and go through every single diff
to check if it actually should be changed.

Fix for #5440

proc without parameters can now be given to
AbstractController::layout

Removed some useless docstrings and no-doc'ed some.

Options :nothing and :text => nil should be handled by
ActionController::Rendering instead.

- instance_variables return symbols in 1.9
- there is instance_variable_defined? method

  from Ruby stdlib.

Rails will now use your default layout (such as "layouts/application") when you specify a layout with `:only` and `:except` condition, and those conditions fail.

For example, consider this snippet:

    class CarsController
      layout 'single_car', :only => :show
    end

Rails will use 'layouts/single_car' when a request comes in `:show` action, and use 'layouts/application' (or 'layouts/cars', if exists) when a request comes in for any other actions.