Version 2.0
Implement vectorization
Created a new branch 'vectorization' to implement it.
	new file:   Vectorization/loadMNISTImages.m
	new file:   Vectorization/loadMNISTLabels.m
	new file:   Vectorization/train-images.idx3-ubyte
	new file:   Vectorization/train-labels.idx1-ubyte
	new file:   Vectorization/vectorization.m