update secret_token code
rails:upgrade:check: Deprecated AJAX helper calls

AJAX javascript helpers have been switched to be unobtrusive and use :remote => true instead of having a seperate function to handle remote requests.
More information: http://blog.jordanwest.me/modest-rubyist-archive/rails-3-ujs-and-csrf-meta-tags

nb: thse are fixes advised by the rake rails:upgrade:check command.
rails:upgrade:check: Deprecated ERb helper calls

Block helpers that use concat (e.g., form_for) should
use <%= instead of <%.  The current form will continue
to work for now, but you will get deprecation warnings
since this form will go away in the future.
More information: http://weblog.rubyonrails.org/
rails:upgrade:check: Deprecated constant(s)
http://litanyagainstfear.com/blog/2010/02/03/the-rails-module/
rails:upgrade:check: Deprecated ActionMailer API
http://lindsaar.net/2010/1/26/new-actionmailer-api-in-rails-3
rails:upgrade:check: Old ActionMailer class API
http://lindsaar.net/2010/1/26/new-actionmailer-api-in-rails-3
rails:upgrade:check: named_scope is now just scope
http://github.com/rails/rails/commit/d60bb0a9e4be2ac0a9de9a69041a4ddc2e0cc914
rails:upgrade:check: Deprecated filter_parameter_logging calls
http://asciicasts.com/episodes/224-controllers-in-rails-3
rails:upgrade:check: Deprecated test_help path
http://weblog.rubyonrails.org/2009/9/1/gem-packaging-best-practices
add changes missed from rails:upgrade:check commits