Change NN library from Keras+TF to scikit-learn

[pplonski]

Right now we use Keras+TF for MLP implementation. Please change to scikit-learn. TF causes many installation problems #167 and it is a large package (>0.5GB).

Please take a look at different MLP performance depending on hyperparameters https://scikit-learn.org/stable/auto_examples/neural_networks/plot_mlp_training_curves.html

[pplonski]

Need to do a comparison of scikit-learn vs keras+TF on few (>5) datasets to check performance.

[pplonski]

I've made the comparison of TF vs Scikit-learn MLP and Scikit-learn MLP looks very good! Details on the blog: https://mljar.com/blog/tensorflow-vs-scikit-learn/ I will change the implementation of MLP to scikit-learn one.