message: handle `exit` command within batch mode
diff: @@ -69,7 +69,13 @@ fn main() {
  let plugins = unwrap_or_return!(args.next(), println_err!("Plugins are not specified"));
  _load_plugins(&command_executor, &plugins)
  }
  - _ if args.len() == 0 => execute_batch(&command_executor, Some(&arg)),
  + _ if args.len() == 0 => {
  + execute_batch(&command_executor, Some(&arg));
  +
  + if command_executor.ctx().is_exit() {
  + return;
  + }
  + },
  _ => {
  println_err!("Unknown option");
  return _print_help();
  @@ -283,6 +289,10 @@ fn _iter_batch<T>(command_executor: &CommandExecutor, reader: T) where T: std::i
  }
  println!();
  line_num += 1;
  +
  + if command_executor.ctx().is_exit() {
  + break;
  + }
  }
  }
  