Merge pull request #58 from jtleek/jeff

finished all dst but nick's stuff + experimental design. holy crap i'm so wiped out i don't want to write experimental design
added a couple more overviews to data science toolbox
added regression overview to ds toolbox course
pred and ML overview for data science toolbox
added beginnings of data products overview to data sci toolbox course -- needs to be completed once we have more material
Merge pull request #59 from ncarchedi/master

The rest of the overviews for data science toolbox course -- see note below
added repo lecture
Merge branch 'master' of https://github.com/jtleek/modules into jeff