Revert "files in the lib directory are no longer autoloaded"

This patch is not consistent since it leaves similar
directories in load_paths, needs more thought.

This reverts commit b5fe014fdc.

railties/lib/rails/engine/configuration.rb

@@ -20,19 +20,15 @@ module Rails
           paths.app.models          "app/models",          :eager_load => true
           paths.app.mailers         "app/mailers",         :eager_load => true
           paths.app.views           "app/views"
-
-          paths.lib                 "lib"
+          paths.lib                 "lib",                 :load_path => true
           paths.lib.tasks           "lib/tasks",           :glob => "**/*.rake"
-
           paths.config              "config"
           paths.config.initializers "config/initializers", :glob => "**/*.rb"
           paths.config.locales      "config/locales",      :glob => "*.{rb,yml}"
           paths.config.routes       "config/routes.rb"
-
           paths.public              "public"
           paths.public.javascripts  "public/javascripts"
           paths.public.stylesheets  "public/stylesheets"
-
           paths
         end
       end

railties/test/application/initializers/load_path_test.rb

@@ -19,7 +19,7 @@ module ApplicationTests
       assert $:.include?("#{app_path}/app/models")
     end
 
-    test "initializing an application allows to load code on lib path inside application class definition" do
+    test "initializing an application allows to load code on lib path inside application class definitation" do
       app_file "lib/foo.rb", <<-RUBY
         module Foo; end
       RUBY
@@ -60,8 +60,6 @@ module ApplicationTests
 
       add_to_config <<-RUBY
         config.root = "#{app_path}"
-        config.cache_classes = true
-        config.load_paths << "#{app_path}/lib"
         config.eager_load_paths << "#{app_path}/lib"
       RUBY