code: def create_scanner(start_row=nil, end_row=nil, *columns, &block)
        columns = (columns.length > 0) ? columns : column_families.keys 
  
        sid = call :scannerOpenWithStop, start_row.to_s, end_row.to_s, columns
        Scanner.new @client, sid, &block
      end
docs: pass in no params to scan whole table