fix "Journals" header setting; refs #110
add datasciencedojo; closes #168
Tukey refs; closes #110
closes #167; changes to msysgit download page

Thanks @justmarkham for improving this; the old way was sort of archaic.
Investigating, I changed to link directly to the
msysgit (windows-specific) page, so that the three platforms are each
directed to something specifically for them (nobody gets directed to the
git-scm site and then has to choose again based on their platform).
n digits for problem 8 example code; closes #165
clean up 538 bash work; closes #166

Thanks @Abodeman for pointing out the problem with the -nrk2 lines!
add Insight; closes #160

Congratulations @lpettingill! Good luck out there! :) :+1:
add Renv ref; closes #156
just a little more wording; closes #149
partial auto-filling
planned and README'd - closes #148
add python anti-patterns; closes #145
add pigpen; closes #144
add UC Berk. twitter videos; closes #143
add neural/deep/nlp/rep to neural; closes #141
rename; both neural nets and deep learning
add refs, closing #142
Merge pull request #169 from ajschumacher/issues

some issues from the issue backlog
rough split between 06 and 07

06 is for base python + a few modules like collections and csv; 07 is
for numpy, pandas, ipython notebook, etc.
new walk-throughs largely done