Added
- visualization_aids::visualize_features added parameters: features: list of feature to visualize,
num_columns: number of columns in the grid, and remove_na: True to ignore NA values when plotting; False otherwise.
Changed
- visualization_aids::draw_tree changed signature to matplotlib coding style
(see [matplotlib Usage Guide](https://matplotlib.org/tutorials/introductory/usage.html#coding-styles)).
- all drawing method now return matplotlib.axes.Axes instead of matplotlib.pyplot.Figure.
Fixed
- Revert import change of sklearn.tree.tree to sklearn.tree due to FutureWarning.