Fixes #14.
Integration test added to verify that edit/update is idempotent.
Replaced modification of RecordsController class in records_controller_spec with an anonymous controller for testing override of set_attributes.

Logic to effectively undo changes to record attributes made by initialize_fields put in collect_form_attributes and called from set_attributes.
Capybara added to test app Gemfile
Methods added to test app generator to fix secret_token initializer and set application controller layout to 'application' to avoid `asset_path' method not found error.