Version 3.4

	modified:   PCAandWhitening/pca_2d.m
	modified:   Vectorization/vectorization.m
	PCAandWhitening/pca_2d.m
		finished Step 1a: Finding the PCA basis
		Finished Step 1b: Check xRot
Version 3.5

modified:   PCAandWhitening/pca_2d.m
		implemented PCAwhit
		implemented ZCA
Version 3.6
Finished the programming exercises of 'PCA and Whitening'.
modified:   PCAandWhitening/pca_gen.m
Version 4.0
softmax will be implemented in this version.
Added softmaxRegression directory.
Copied the original code from Stanford's Website.
	new file:   softmaxRegression/softmaxCost.m
	new file:   softmaxRegression/softmaxExercise.m
	new file:   softmaxRegression/softmaxPredict.m
	new file:   softmaxRegression/softmaxTrain.m
	new file:   softmaxRegression/train-images.idx3-ubyte
	new file:   softmaxRegression/train-labels.idx1-ubyte