Renamed AbstractApplicationController and abstract_application.rb to ApplicationController and application.rb, so that it will be possible for the framework to automatically pick up on app/views/layouts/application.rhtml and app/helpers/application.rb

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@159 5ecf4fe2-1ee6-0310-87b1-e25e094e27de