Add book listing

* Renamed AddListingActivity to better reflect its actual purpose. It is now InputISBNActivity. 
* Created REAL AddListingActivity which displays the page where the data is autopopulated and you simply have to put in a price. 
* Ellipsized the item views of all three tabs so that it doesn't wrap around.
* Reworked Book creation into a static method in the Book class, which accepts a JSONObject of kind=book.(need to do same for listing and course)
* Made Book implement Parcelable so that we can pass book objects around as parameters in a putExtras() of an intent.