* add seq2seq infer

* update argument description, remove useless import

* add deploy directory

* add deploy directory, add relative import

* update arg usage in README, fix import order.

* update __init__

* fix readme version info

* update __init__

* update seq2seq example, using bleu

* remove target file arg

* update readme

* update __init__

* update couplet api usage, delete useless import

* update seq2seq readme

* update seq2seq readme path

* update seq2seq, using paddlenlp

* Using new paddlenlp API

* update seq2seqREADME

* wrap dev ds

* delete useless comments

* update predict.py

* using paddlenlp.bleu

* remove shard

* update README, using bleu perl

* delete cand

* Remove tokens that make sentences longer than max_len

* remove pdb

* remove useless code.

* update url and dataset name of vae dataset(ptb and yahoo)

* update seq2seq and vae, data and README