* Update learning.py

* Add Euclidean Distance

* Update learning.ipynb

* minor fix in notebook

* minor spacing in learning.py

* Added Euclidean Test

* Bugfixing

* Test for "exclude"

* Update test_learning.py

* update_values

Add DecisionTreeLearner, NeuralNetLearner and PerceptronLearner tests

* Add flake8 config file

* Fix flake8 for test files

- Added tests for PluralityLearner, NaiveBayes and kNN algorithms

- Replace parse_csv with non-trivial input