Updating eigenfaces and adding online and "the homework review process"
Merge branch 'master' of https://github.com/yoavfreund/UCSD_BigData
Adding docs notebook directory
Changed notebookCollections.md
updating online optimization
update notebook
Updated the directions for doing and reviewing HW.
added docs to NotebookCollections.md
Adding several files.
Merge branch 'master' of https://github.com/yoavfreund/UCSD_BigData

For now, ignoring the conflicts in EigenFaces.ipynb, Regression.ipynb, and Regression_sklearn.ipynb (not committing these).
Manually fixed conflicts with newly released version of EigenFaces.ipynb.
Finished the new problems in EigenFaces.ipynb. Made code more general so that it could be reused for problem 3, which involved performing iterative PCA across different faces. Also created a general way to compute many reconstructed images using the same number of eigenvectors.