Merge pull request #18 from justmarkham/master

added some links to the list of data sources
yet more projects! thanks @justmarkham
better filenames
Merge branch 'master' of github.com:ajschumacher/gadsdc
initial cleanup of lm.Rmd
some cleanups
add old pace file
add IDRE ref
add a lot more to lm demo
model matrix sufficiently talked about
add another note on design matrix care
class flow laid out
add period
focused slides, aligned walk-through
add some on model selection
initial reg slides
add modified Hastie walk-through
questions in
add questions
maintain thread of questioning