Sync with latest Instiki trunk. Changes:

1) Upgrade Rails to 1.2.3
2) Revert RedCloth to previous version (who %#$@ cares?)
3) Preserve the Rails Security fix  to vendor/rails/actionpack/lib/action_controller/caching.rb from Revision 80.

vendor/rails/railties/lib/commands/console.rb

@@ -1,4 +1,4 @@
-irb = RUBY_PLATFORM =~ /mswin32/ ? 'irb.bat' : 'irb'
+irb = RUBY_PLATFORM =~ /(:?mswin|mingw)/ ? 'irb.bat' : 'irb'
 
 require 'optparse'
 options = { :sandbox => false, :irb => irb }