Merge pull request #68 from ConvLab/clean_code

convlab/util/__init__.py

convlab/util/unified_datasets_util.py

data/unified_datasets/camrest/database.py

data/unified_datasets/camrest/ontology.json

data/unified_datasets/taskmaster/README.md

data/unified_datasets/taskmaster/data.zip

data/unified_datasets/taskmaster/ontology.json

data/unified_datasets/taskmaster/original_data.zip

data/unified_datasets/taskmaster/preprocess.py

data/unified_datasets/woz/ontology.json