rust port of python in http://neuralnetworksanddeeplearning.com/chap1.html

main goal: me understanding what's going on

done:

• implementation that 'works' without runtime errors

to do:

• verify correctness
• add unit tests
• train using actual training data
• evaluate with test/validation data
• make more efficient

training_data/test_data not included format: json: [{"x":[float;784], "y": u32}] => x: 28x28 gray image as float => y: label 0.. 9

the data can be found here: https://github.com/mnielsen/neural-networks-and-deep-learning/blob/master/data/mnist.pkl.gz albeit in a different format