Removed obsolete "advanced" plugin URLs.

These plugins are obsolete even for Rails 2, they have no place in a Rails 3 guide.
Also removed "mad cool" reference.

If anyone has ideas about cache plugins that *must* be included, I would love to know.
As far as I am concerned the rails guides should stick to built-in methods and have a
simple list of references for people wishing to investigate further.

I will check out the references after this commit to see if they're up to date.

railties/guides/source/caching_with_rails.textile

@@ -362,13 +362,6 @@ class ProductsController < ApplicationController
 end
 </ruby>
 
-h3. Advanced Caching
-
-Along with the built-in mechanisms outlined above, a number of excellent plugins exist to help with finer grained control over caching. These include Chris Wanstrath's excellent cache_fu plugin (more info "here":http://errtheblog.com/posts/57-kickin-ass-w-cachefu ) and Evan Weaver's interlock plugin (more info "here":http://blog.evanweaver.com/articles/2007/12/13/better-rails-caching/ ). Both of these plugins play nice with memcached and are a must-see for anyone
-seriously considering optimizing their caching needs.
-
-Also the new "Cache money":http://github.com/ngmoco/cache-money/tree/rails3 plugin is supposed to be mad cool.
-
 h3. References
 
 * "Scaling Rails Screencasts":http://railslab.newrelic.com/scaling-rails