Session3 -- mailroom check-in

Nearly done with mailroom.py.  Still need to add final if __name__ ==' __main__' block but the other components are finished so it seemed like a good time to check in.  
if you make each reocrd a tuple, it will keep the name and donation list linked, but the dontation list can still be mutable -- i.e. a list:

donor_record = ( 'A name', [34, 67,] )

no you can't change the name or put a different list in the record, but you Can add something to the list.