* cmd.c, tree.c: Updated to the new file.c api.
* file.c: (copy_file_file, copy_dir_dir, move_file_file,
move_dir_dir): Updated to work with the new updating stuff.
* setup.c: New configuration option to compute the totals to be
transfered.
* file.c (compute_dir_size, panel_compute_totals): New routines to
compute the total ammount of information that is going to be
transfered.