text: Title: Are special tokens wrong?
  Body: In the vocab of llama, eos_token is "\</s\>", bos_token is "\<s\>", unk_token is "\<unk\>", and the corresponding token ids are 0, 1, 2.
  So I think in train.py, [line 214-221](https://github.com/tatsu-lab/stanford_alpaca/blob/main/train.py#L214) should be removed.
  
  And  are [DEFAULT_BOS_TOKEN](https://github.com/tatsu-lab/stanford_alpaca/blob/main/train.py#L30) and [DEFAULT_UNK_TOKEN](https://github.com/tatsu-lab/stanford_alpaca/blob/main/train.py#L31) wrong?
  
  And for [line 151](https://github.com/tatsu-lab/stanford_alpaca/blob/main/train.py#L151), should we add a space between example['output'] and tokenizer.eos_token?