def move_column ix, newix
      acol = @chash.delete_at ix
      @chash.insert newix, acol
      _invalidate_width_cache
      #tmce = TableColumnModelEvent.new(ix, newix, self, :MOVE)
      #fire_handler :TABLE_COLUMN_MODEL_EVENT, tmce
    end
def move_column ix, newix
      acol = @chash.delete_at ix
      @chash.insert newix, acol
      _invalidate_width_cache
      #tmce = TableColumnModelEvent.new(ix, newix, self, :MOVE)
      #fire_handler :TABLE_COLUMN_MODEL_EVENT, tmce
    end
should all this move into table column model or somepn
 move a column from offset ix to offset newix