This revision includes the following changes:
 - [1] The admin folder was added directly under the "book-exchange" plugin folder to hold all of the scripts which will be used to administer the plugin from the Wordpress Administration section of the site.
 - [2] book-exchange.php was modified to include an action hook to add the Book Exchange management tools to the Wordpress Administration menu.
 - [3] The Admin class was added to fetch data from the database for use in the plugin administration.
 - [4] The Settings class was added to generate and display the form items which are shown on the Book Exchange settings page in the plugin adminstration.