# Conflicts:
#	test/core/test_trainer.py

2. loss中修复一个错误
3. metric中fast_param调整

* fix FieldArray type check bugs

2. trainer中update_every改为print_every, 因为update_every可能引起optimizer update的误解
3. fieldarray content支持使用np.ndarray初始化

# Conflicts:
#	fastNLP/core/dataset.py
#	fastNLP/core/trainer.py
#	test/core/test_trainer.py

Trainer support print_train and tqdm train.

* fix losses的_fast_param_map的bug
* Trainer添加sampelr初始化参数，并调整参数顺序
* refine codes

* 更新Loss的接口形参跟metric保持一致
* 添加对几种loss的测试
* embed_loader采用维度独立的方法采样
* 对应测试代码的修改

* improve Loss initialization interface
* improve test codes for trainer

* fix bug in DataSet.split
* fix bugs in FieldArray, to allow content as a list
* fix bug in losses check
* ...

optimizer.SGD(lr=xxx);如果没有传入parameters，则在trainer中帮他加入parameter

* refine code style
* set up unit tests for Batch, DataSet, FieldArray
* remove a lot of out-of-date unit tests, to get testing passed

- apply DataSet in Predictor; remove sub-predictors; add "task" argument to specify which task to predict, as how Trainer/Tester did.
- remove Action class
- add helper function for DataSet, to create DataSet easily
- more code comments
- clean up unnecessary codes
- add unit tests for Batch, Predictor, Preprocessor, Trainer, Tester