First pass at 3.1.12 update
Merge branch 'rails-3' into rails-3.1.12
Change RAILS_ROOT to Rails.root
Rails 3.0 clone behavior is now dup in Rails 3.1 (http://rubyrailsandwindows.blogspot.com/2011/09/duplicate-model-in-rails-31.html)
More clone->dup changes