Merge pull request #9 from Gimperion/master

tidy up R-base gfx
minor updates backlog and placeholders
this journal was suggested
add another twitter book
example/extension monty hall
warn cheaters
add official py tutorial
might as well do this one too
better to use `parallel`
clean up; add a little
add directions for file submission
wording fix
expand slides a little
consistent naming
simplify; just for training error
consistent question review
one more question
more for kaggle day