Refine api docs and readme and fix baseline bug (PaddlePaddle#912)

* fix unified transformer dtype problem

* fix win dtype bug

* Fix plato-2 and plato-mini dtype bug

* Fix plato-2 tokenization

* Refine some doc

* Add general k support for topk sampling

* fix seed

* minor fix

* Fix unitransformer readme

* topk kernel optimization

* add unimo model and fix generate api

* add 3 datasets for unimo-text

* fix tokenizer bug

* paddlenlp+lightseq sample

* Refine api docs and readme and fix baseline bug

* add shell srcipt

* remove lightseq samples

* minor fix

* minor fix

Co-authored-by: Jiaqi Liu <[email protected]>
Co-authored-by: liu zhengxi <[email protected]>

update ernie text cls ci (PaddlePaddle#823)

* add ernie text cls ci

* mv ernie_text_cls_params.txt to ernie_text_cls directory

update doc of wordtag

Simplify transformer.rst code block

Simplify transformer.rst code block

Add course homework answer (PaddlePaddle#583)

* Fix dataset doc

* fix dataset doc

* Change load_dataset design for loading local dataset

* Update softmax_with_cross_entropy to cross_entropy

* Fix community provided datasets and fix cross_entropy for elmo and dgu

* Add course homework answer

Update README

tag v2.0.0

fix deadlink (PaddlePaddle#423)

fix badge error