Package Lists Manager

This class will handle the reading of the APT package lists from the local system or the internet. The methods for this class will be open (to start reading), get_next_package (to read the next package from a file), at_end (a flag to state that all the files have been read), and close (to close the last file). The initialization of this class will create the list of local files to read or it will create a list from the downloaded packages from the internet.