Prices, in and out functions, comments

I've finished the Prices class and written the read from file and write
to file functions in GlobalFunctions, Hotel, Room, Single, Double,
Suite, Reservation and Bill so that they work with the .DTA files I made
earlier. I've also commented my code. We still need the E1, E2, E3, O1,
O2, O3, O4, O5, O6, O7, H and T commandoes in the switch in main, and
som additional functons.