kes Make find with no args in tree restore return error rather than

     stopping the selection. Fixes bug #665
kes  Rework DVD writing to ensure that the last part is written
     on open_next_part when dealing with a spool file.
kes  Correct the lseek_dev() routine to handle end point correctly
     (bug introduced by me).
kes  Allow part number to exceed num_dvd_parts in lseek_dev().