* Add tutorial about nlp dataset customization

* Update doc and tokenizer usage in seq-cls demo

* Updata tutorial

* Add token-cls task for transformer modules

* Fix numpy dtype mismatch in windows

* Update README.md

* Update token-cls task for ernie_tiny

* Update token-cls task for ernie_tiny

* Update token-cls task for other Transformer modules

* Update README.md of modules and token-cls demo

* Add chunk_scheme arg check in SeqLabelingDataset

* Update ChunkEvaluator and paddlenlp requirement

* Update README.md

* Update token-cls demo

* Add MSRA dataset

* Add ernie_tiny seq-cls task case

* Update README.md