OCR for digits 0-9 with tests.

This is a first draft for a simple OCR using a Backpropagation algorithm (http://en.wikipedia.org/wiki/Backpropagation). The `data.csv` file contains 5000 images of digits, 0-9. Each image is 20x20 pixels. Each line of `dataLabels.csv` represents the expected digit depicted in the image of the respective line from `data.csv`.

The two data files were modified/adjusted from an online Machine Learning course here: https://www.coursera.org/course/ml