v0.3.0

• Refactor. Please refer to the Design Overview session in docs for more details.
• Support both matplotlib and plotly.
• Update tutorials according to the refactor codes.
• Better unit test.
• Semi-automate dosctring generation.

Update for newer versions of dependent packages

• Update tutorials for xgboost==1.3.3
• Add simple model training in tutorials for better understanding and reproducing
• Fix charts for matplotlib==3.1.1
• Remove large .pkl files, use separate files for data (*.csv), info (features, target in *.json), and model (.pkl)
• SImplify unit tests, removing all model-dependent test cases
• Fix issues in Tox and Travis CI