Add notes on DataAnalysis week 3.

Clustering
Dimensionality reduction
ProgLang HW3 Prob 1-3
ProgLang HW3 prob 4
ProgLang hw3 Prob 5
ProgLang HW3 Prob 7
ProgLang HW3 prob 6
ProgLang HW3 #8 works, but trying to improve.
DataAnalysis HW3 complete.

Includes problems on SVD and Hierarchical clustering (hclust)
Also has functions for finding number of clusters at a given
depth of the dendrogram.
ProgLang hw3: Still stuck on #8