Upgrade to Rails 2.2.0

As a side benefit, fix an (non-user-visible) bug in display_s5().
Also fixed a bug where removing orphaned pages did not expire cached summary pages.

vendor/rails/activemodel/lib/active_model.rb

@@ -1,17 +1,5 @@
-$LOAD_PATH << File.join(File.dirname(__FILE__), '..', '..', 'activesupport', 'lib')
-
-# premature optimization?
-require 'active_support/inflector'
-require 'active_support/core_ext/string/inflections'
-String.send :include, ActiveSupport::CoreExtensions::String::Inflections
-
-require 'active_model/base'
 require 'active_model/observing'
-require 'active_model/callbacks'
-require 'active_model/validations'
-
-ActiveModel::Base.class_eval do
-  include ActiveModel::Observing
-  include ActiveModel::Callbacks
-  include ActiveModel::Validations
-end
+# disabled until they're tested
+# require 'active_model/callbacks'
+# require 'active_model/validations'
+require 'active_model/base'