Hdlib

Add:

- Add `error_rate` as `model.Model` class method for computing the error rate of a classification model.

Fix:

- The `model.Model.predict` function computes the error rate before retraining the classification model.

Fix:

- Fix the retrining process in `model.Model.predict` to avoid overfitting.

:warning: Avoid using previous versions of `hdlib`.

Fix:

- Fix the initialization of Vector objects with a specific seed;
- `model.Model._init_fit_predict` and `model.Model._stepwise_regression_iter` are now private;
- Improving docstring adopting the [numpydoc](https://numpydoc.readthedocs.io/en/latest/) documentation format.

Fix:

- Fix the break condition in `model.Model.stepwise_regression` for both the `backward` and `forward` methods.

Add:

- Add `stepwise_regression` as `model.Model` class method for performing the feature selection as backward variable elimination or forward variable selection

Add:

- Add `bind`, `bundle`, and `permute` as `Vector` class methods for applying arithmetic operations inplace;
- Rename `split_dataset` in the `parser` module into `kfolds_split`;
- Add `percentage_split` function to the `parser` module;
- Integrate [chopin2](https://github.com/cumbof/chopin2) ML model into the `model` module withe the `Model` class.