title: "-[__NSCFArray removeObjectAtIndex:]: mutating method sent to immutable object" error
body: <p>I have a static NSMutableArray, and this array is the data source of my table view. Then I delete a cell from my table view and it crashes.</p>
  
  <p>here is where I create the array:</p>
  
  <pre><code>static NSMutableArray *listaPiscinas;
  </code></pre>
  
  <p>my code:</p>
  
  <pre><code>-(void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath
  {
      if (editingStyle == UITableViewCellEditingStyleDelete) {
  
          [listaPiscinas removeObjectAtIndex:indexPath.row];
          [tableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:YES];
          [TratamentoView setListaPiscinas:listaPiscinas];
          NSString *URLdeletarPiscina = [[NSString alloc] initWithFormat:@"%@app/excluir_piscina.php?cod_cliente_piscina=%@", URL_CADASTRO, [[listaPiscinas objectAtIndex:indexPath.row] objectForKey:@"cod_cliente_piscina"]];
          dataReciever = [[AsyncDownloader alloc] initWithGetAdress:URLdeletarPiscina delegate:self];
  
          [tableView reloadData];
      }
  }
  </code></pre>