clarified datasets is part of R not RStudio
first draft of third lesson in multivariable examples
updated manifest to include multivarexamples3
fixed up multivar examples3
fixed lesson examples3
Merge remote-tracking branch 'kuiper/master'
Merge branch 'master' into MVEX3
clarified lesson for mvex3
Merge remote-tracking branch 'kuiper/master'
Merge branch 'master' into MVEX3
minor corrections
typo: fourth instead of forth

Fixed a typo, it's "fourth" instead of "forth", it referes to the number 4.
Merge pull request #19 from tiangolo/patch-1

typo: fourth instead of forth
update hint to reflect new variable name