move views, controllers, and helpers under the radiant/admin namespace where necessary

This is a large commit and includes some unrelated changes.
When trying to get the application working on the spec/dummy app, I made changes to the way some controller
methods are defined in the provided application controller.

This also adds an admin controller which provides the session and login methods.

A minor change to the login form page was made to remove reference to the type of boot (gem vs. vendor)
initialize haml templates
fix references from request_uri to fullpath
rely on admin controller to handle the authenticate and authorize before filters
require will_paginate view helpers in the pagination controller
whitespace
move Radiant.config to Radiant.detail
remove bad alias for fullpath
fix the namespacig for welcome controller and remove export controller routes