add slides
Update index.html

Added link to slides for docopt presentation
Added SPRINT slides
Merge pull request #16 from edwindj/patch-1

Update index.html
Added SPRINT slides.
Merge pull request #17 from eilidh-t/master

Added SPRINT slides
add slides john chambers
Added PivotalR slides and demo scripts
Merge pull request #18 from walkingsparrow/master

Added PivotalR slides and demo scripts