fixed comment
added method header for to_string to neurla_network
nn to_string and constructor working as expected
added a train method header
setup training method and file reading
training function now takes a learning rate
removed faulty code from train mehtod
general framework of train method set up
changed things to make it work
2 level neural network implemented
removed comments and added debug mseoutput
fixed some bugs in backpropagation algorithm
reordered operations in neural_network propagate_backwards method
converted all floats to doubles
corrected what seems to be a large implementation bug