Added Functionality to Book Management

I spent some time yesterday programming additions for Book Management.

Sellers can now see how many buyers want to buy their books and they can see the buyer contact information.

Buyers can see which books they have requested and whether the seller has deleted the book.

In the future I plan on adding functionality so sellers can see which books they have deleted. They will also be able to change the reason why they deleted it (this is so I can track the success of the Bookexchange).