* Add render_views for admin/settings spec
* Add coverage for admin/settings#update
* Add coverage for admin/settings typecasting open_registrations setting
* Simplify how admin/settings finds the value for updating
* Rely on activerecord to not update a value that hasnt changed
* Add coverage for non-existent setting
* Use a constant for boolean settings
* Add Admin::BaseController to wrap admin area
Extracts the setting of the `admin` layout and verifying that users are admins
to a common base class for the admin/ controllers.
* Add basic coverage for admin/reports and admin/settings controllers