* distinguish logits, logits_softmax
* modity last layer softmax config for model_zoo
* fix 'prediction_scores' problem for regression task.
* fix wrongly written words
* fix logits_softmax problem for regression.
* fix logits_softmax problem for slot tagging task.
* Update Tutorial.md
* fix CPU train --> GPU test, GPU train --> CPU test. But CPU train --> multi-GPU test will report error.
* remove ujson
* remove glove for model_zoo/demo/conf.json
* modify glove for Tutorial.md
* add nltk.download('punkt') in problem.py