This revision includes the following changes:
 - [1] The images/book-covers directory and its contents have been added to include placeholder images for books whose covers are pending approval, inappropriate, or unavailable.
 - [2] suggest.php has been updated to follow the new standards of the of the Book::getBookByISBN() method by catching thrown exceptions. It's functionality has also been enhanced to provide a listing of available book covers in the even the user requests information on a book which the exchange does not yet have on record.
 - [3] app/index.php includes minor HTML semantic alterations.
 - [4] FFI_BE_Explore.js includes minor alterations to the included documentation.
 - [5] FFI_BE_Sell_Books_Assistant.js has been fully documented. It's functionality has also been enhanced to provide the user with a listing of book covers to choose from in the event that the server suggests a book cover instead of supplying a set of data on a particular book. If the server supplies a set of data for a particular book, this plugin will now show the cover which has been selected for the book. The semantics for the course suggestion buttons have been updated to use a Twitter Bootstrap styled button group.
 - [6] sell.js has been updated to include a custom validation prompt for a missing book cover. It also now uses TinyMCE 4 as the WYSIWYG editor.
 - [7] sell.superpackage.min.js includes the changes documented for FFI_BE_Sell_Books_Assistant.js and sell.js.
 - [8] sell-books/index.php was updated to use the newly renamed PHP classes which help build the page. It also includes a reduced set of CSS and JS files as they have been minified and consolidated in to a super package file.
 - [9] sell.css has been brought up to new CSS standards. The classes for each section of the page it styles has been broken up by the <section> it styles on the sell-books page. Fully qualified class names have been added to classes in cases where their names had been previously relative. The styles for the course suggestion buttons have been changed to use the Twitter Bootstrap styled button group. This stylesheet simply makes these buttons responsive by leaving them as vertical for wide screens, then making them horizontal for smaller screens. A minor issue with the courses table spilling over into the <section> padding has also been corrected.
 - [10] sell.superpackage.min.css includes teh changes documented for the sell.css stylesheet.
 - [11] book-prompt.jpg was added as a placeholder image on the sell-books page until an appropriate book cover image can take its place.
 - [12] The Cloudinary class now includes the ability to check the status of an image, to see if a placeholder image should be suggested, before going to Cloudinary to fetch the book cover there.
 - [13] The IndexDen class now includes the ability to add a book to the index, update all books in the index which match a particular ISBN, or just update a single book by its sale ID. A possible bug was also corrected in the reloadIndex() method in the event that the server did not return a response after indexing a batch of documents.
 - [14] The Book class now features the ability to get information about a book by its ISBN, and also fetch a listing of possible book covers from the Google Shopping API when given the ISBN.
 - [15] The Course class was updated to use the new ffi_be_courses relation (instead of ffi_be_new_courses) when fetching a listing of courses.
 - [16] The Sell_Book_Display class was updated to disable all ISBN input fields when updating a book. It will display information for the new book cover section of the sell-books page. The "Condition" input field was updated to include a responsive set of text to display on smaller screens. Minor references to data imported from the database have also been applied.
 - [17] The No_Data_Returned exception has been added to be thrown in the event that no data from a database query is returned.
 - [18] The Purchase_Process class has been updated to include minor change to the style of existing documentation. The previously un-documented updateLocal() method has now been documented.
 - [19] The Sell_Book_Process class has been added to insert or update an existing book on the exchange. This information will also be sent to the IndexDen index.