This revision includes the following changes"

 - [1] searching.gif was renamed to searching-large.gif, since searching-small.gif was also added for use on the sell-books/index.php page as suggestions are retrieved
 - [2] The sell-books/index.php page includes several new JS and CSS files for actions such as validation and book suggestions. The logic for creating the courses table has been isolated into the Sell_Book_Display class
 - [3] The explore.css includes as minor change which adjusts the section.welcome item so that it's z-index is in front of the <body> tag (i.e. not longer at z-index: -1)
 - [4] The Book_Overview now includes a method for fetching a books by its ISBN-10 or ISBN-13 value, designed for use as part of the sell-books/index.php suggestion logic
 - [5] The Sell_Book_Display class includes logic to create the dependent courses table for the sell-books/index.php page
 - [6] suggest.php was added as the page which will suggest the book information based on the ISBN-10 or ISBN-13 on the sell-books/index.php page
 - [7] The FFI_BE_Sell_Books_Assistant.js and ISBN.js files work together to validate the ISBNs on the sell-books/index.php page and suggest the book information based on the either the ISBN-10 or ISBN-13 value
 - [8] The jquery.validationEngine-en.js, jquery.validationEngine.js, and validationEngine.jquery.css have been added to validate text input on the sell-books/index.php page
 - [9] The sell.js has been added to initalize the validation, suggestions, and TinyMCE on the sell-books/index.php page
 - [10] Isbn.php was added as a third-party class for validating ISBNs on the server-side. As of now, it is only used in the Book_Overview class for suggesting book information