action_cache plugin now has x-sendfile support

My action_cache plugin, in addition to it's previous goodness, now has
support for lighttpd's x-sendfile header.

The code is here: http://craz8.com/svn/tags/plugins/0.1.0/action_cache

Check out the README for features, and how to use the x-sendfile
functionality. I've only tested this with lighttpd 1.5.0 latest source
- I couldn't get 1.4.13 to work as documented.

Checkout my blog - http://blog.craz8.com - for some things you can do
with the plugin that can't be done with Rails built in action caching.