write out acronym: Alternating Least Squares
add amazon review data link; closes #46
update ref to new location
remove time-dependent ref. to SVM
add ref to Strang paper; closes #42
add questions and ref for 20; closes #54
add some questions; closes #49
standardize notation to X for raw data
add pca/svd run-through; closes #45
Merge pull request #209 from ajschumacher/recommend

'recommend' updates; really mostly dim. reduc. etc.