updated mainly SystemManager class (already using last update of Jon)

-fixed Journals, Book,  Magazine and Newspaper so they inherit from
Reservation

-Library -> the array of Section now has Magazines, Journals and
Newspapers sections

-SystemManager:
-add login(...), which checks if user is a librarian or generalUser, and
then call loginGeneralUser(...) or loginLibrarian(...)  (both are
private now).
-fixed searchBook(...). Now it returns an ArrayList of Books instead of
a String.
-added giveOutBook(...)
-added receiveBook(...) (it is incomplete, it needs to set user's fine.