code: protected boolean isCommandPrefix (String enteredCommand, String handlerCommand,
          CommandHandler handler, BodyObject user)
      {
          return handlerCommand.startsWith(enteredCommand) && handler.checkAccess(user);
      }
docs: Returns true if <code>enteredCommand</code> equals or is a prefix of
  <code>handlerCommand</code> and if the handler is available for <code>user</code>.