No biases saved in Storage.swift

[ferrazza]

Hi, I noted different output values (with same input) after saving and restoring a neural network in url. I discovered that in saving methods of neural network (Storage.swift), only weights are saved but not biases. Little modifications to save and restore both weights and biases correct this issue.

[plivesey]

Oh man...thanks for reporting this! I didn't notice this, but clearly causing problems. I'll add it to my pr #10.