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/railties/lib/commands/runner.rb

@@ -41,7 +41,7 @@ require RAILS_ROOT + '/config/environment'
 if code_or_file.nil?
   $stderr.puts "Run '#{$0} -h' for help."
   exit 1
-elsif File.exists?(code_or_file)
+elsif File.exist?(code_or_file)
   eval(File.read(code_or_file))
 else
   eval(code_or_file)