Allow estimators to be cloned

[rasbt]

Description

Adds get_params and set_params methods so that mlxtend estimators can be cloned via scikit-learn's clone function.

Related issues or pull requests

Fixes #372

Pull Request Checklist

• Added a note about the modification or contribution to the ./docs/sources/CHANGELOG.md file (if applicable)
• Added appropriate unit test functions in the ./mlxtend/*/tests directories (if applicable)
• Modify documentation in the corresponding Jupyter Notebook under mlxtend/docs/sources/ (if applicable)
• Ran nosetests ./mlxtend -sv and make sure that all unit tests pass (for small modifications, it might be sufficient to only run the specific test file, e.g., nosetests ./mlxtend/classifier/tests/test_stacking_cv_classifier.py -sv)
• Checked for style issues by running flake8 ./mlxtend

[pep8speaks]

Hello @rasbt! Thanks for updating the PR.

• In the file mlxtend/externals/signature_py27.py, following are the PEP8 issues :

Line 173:80: E501 line too long (80 > 79 characters)

Comment last updated on April 25, 2018 at 02:41 Hours UTC

[coveralls]

Coverage decreased (-1.0%) to 90.909% when pulling 27efc5e on getparams into 6313cd1 on master.