updated bs4 module version in HW0
modified prob 3(a) to include E(Y)=0
modified 3(b), 3(c) to include year 2012
clarified Prob 1(b) in HW1
fixed switch typo in HW0_solutions.ipynb
changed prob 1(b) and 1(c)
fixed typo
added Lab2_Notes.ipynb
added link to download Lab2_Notes.ipynb
updated to ipython 2.2.0; re-posting HW1.ipynb
fixed typo
corrected download link to raw.github.com
try 2 to fix github download link
added cell for solutions in 1(c)
Revert "added cell for solutions in 1(c)"

This reverts commit e9e4635dcd57d854a8c44128a58b511922ce2b17.
Revert "try 2 to fix github download link"

This reverts commit 7f2a239371a192edd6cd0c67429ac8cc06be4738.
Revert "corrected download link to raw.github.com"

This reverts commit 839cc2202413da75ecbab6d15eaa2535ed5b34b6.
Revert "fixed typo"

This reverts commit ba11d10f7cbfd3147d21fb130f1c0790fcefec85.