Adds no_cols columns before col, appends if col > maxcols

        and marks grid as changed

def insert_cols(self, col, no_cols=1):
        """Adds no_cols columns before col, appends if col > maxcols

        and marks grid as changed

        """

        # Mark content as changed
        post_command_event(self.main_window, self.ContentChangedMsg)

        tab = self.grid.current_table

        self.code_array.insert(col, no_cols, axis=1, tab=tab)