Use ruby 2.0.0 on heroku
Enhance CSRF protection by requiring POST for non-idempotent controller actions

Remove code related to demo mode while here.
Switch test suite to capybara based one instead of unicorn/net-http/hpricot hybrid

While here, add capybara-webkit based integration test suite with unicorn,
only used on ruby 1.9+.

Fix some small issues found by said test suite.
Minor unit test changes for Sequel 4 compatibility
Require Sequel active_model plugin

Sequel 4's default Errors class will not be compatible with
Rails helpers by default.
Add forward compatibility for future default deep join qualification in Sequel
Upgrade to Rails 4

This still allows use of Rails 3.2.12 on ruby 1.8.7.
Serve static assets in production

This appears to be necessary for the demo site on Heroku.