Conflicts:
	railties/test/initializer/initialize_i18n_test.rb
	railties/test/initializer/path_test.rb

Fix the documentation for root :to. It should use a fully qualified controller#action syntax (Closes #3606)

Fix ActionMailer. The fact that ActionMailer::Base does not inherit from AbstractController::Base is either a bug or we need to re-evaluate the requirements of the mixins.

Turn filter_parameter_logging on by default for password and password_confirmation and remove contentless comments

AC::Head now doesn't have an unfulfilled Rendering dependency, and instead works just fine standalone (which means that ConditionalGet also doesn't have a Rendering dependency)

Added ActionDispatch::Request#authorization to access the http authentication header regardless of its proxy hiding [DHH]