Upgrade to Rails 2.0.2

Upgraded to Rails 2.0.2, except that we maintain

   vendor/rails/actionpack/lib/action_controller/routing.rb

from Rail 1.2.6 (at least for now), so that Routes don't change. We still
get to enjoy Rails's many new features.

Also fixed a bug in Chunk-handling: disable WikiWord processing in tags (for real this time).

vendor/rails/actionpack/lib/action_controller/cgi_ext.rb

@@ -0,0 +1,16 @@
+require 'action_controller/cgi_ext/stdinput'
+require 'action_controller/cgi_ext/query_extension'
+require 'action_controller/cgi_ext/cookie'
+require 'action_controller/cgi_ext/session'
+
+class CGI #:nodoc:
+  include ActionController::CgiExt::Stdinput
+
+  class << self
+    alias :escapeHTML_fail_on_nil :escapeHTML
+
+    def escapeHTML(string)
+      escapeHTML_fail_on_nil(string) unless string.nil?
+    end
+  end
+end