in Manager.java :
-included ArrayList of ArrayList to store the library content of albumList, movieList, and audiobookList.
-included a check to make sure the manager can change what he wants to by needing to type in the username and password before being allowed to make certain changes to the library files.
-included a check for if the library was already added.
-included add Library functions for each of the three types of media
-included a remove for removing certain elements for each type of media
-included a removeAll for each of the media, which removes all of the content in the library
-included checks for getting the number of each library object sold
-included checkTotalSales to check for the total media contents sold *review this*
-included a retrieveConsumerInfo to retrieve all the information for any Customer Account
-included a toString()

Also, updated the import files and descriptions