chp 10
Merge branch 'gh-pages' of https://github.com/johnstart/data-science into gh-pages
chp14 ripe's work complete
Merge pull request #32 from ripeconan/develop

chp14 ripe's work complete
Merge pull request #33 from flymark2010/develop

chp9 completed.
Revert "chp9 completed."
Merge pull request #34 from johnstart/revert-33-develop

Revert "chp9 completed."
commit again