Delete multiple columns from multiple sequences
(delete a column of positions).  You will be prompted for
a) which sequences to act on (default to the current sequence),
b) at which position to do the deletions (default to the 
   current cursor position, and
c) how many positions to delete (default to MULT)
NOTE that DELETE-COLUMNS observes the status of the
variable PROTECT. If one attempts to delete non-gaps
when PROTECT is set, you will be asked how to
proceed.  You may 
a) PRESERVE this sequence and continue to act on subsequent sequences,
b) OVERRIDE protection of this sequence - delete positions in
   this sequence regardless of the protection, or 
c) ABORT the delete operation.