Delete entries in slots header
and species
orphaned by manipulation of
slots.
Orphaned records generated by modifications in some slots may cause a loss
on the validity of vegtable objects.
This function should be applied to optimise the allocated size of a
vegtable object, as well. Since running cleaning only
once does not assure the deletion of all orphaned entries, it is recommended
to run it at least twice. This repetition of cleaning is controlled by the
argument times
.