New version of Spork

I've updated the section on Spork in the Ruby on Rails Tutorial book to use the new Spork release candidate, which works with Rails 3. There are several changes to the sample app config files; see the commit at GitHub for the details (or clone the sample app repo). Note: Peter Cooper has a post on Rails, RSpec, and Spork that has an extra line (config.cache_classes = false in config/environments/test.rb) that I don't find necessary; please let me know if your experience is different.